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Ulcerative dermatitis dm broiler chickens: The effectsof wet litterM.F. Martland aa Houghton Poultry Research Station , Houghton Huntingdon, Cambs., PE17 2DA, EnglandPublished online: 02 Jan 2008.

To cite this article: M.F. Martland (1985) Ulcerative dermatitis dm broiler chickens: The effects of wet litter, Avian Pathology,14:3, 353-364, DOI: 10.1080/03079458508436237

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Avian Pathology, 14: 353-364, 1985

ULCERATIVE DERMATITIS DM BROILER CHICKENS:THE EFFECTS OF WET LITTER

M.F. MARTLAND

Houghton Poultry Research Station, HoughtonHuntingdon, Cambs., PE17 2DA, England

SUMMARY

Wet litter induced severe ulceration of the skin of commercial broilerchickens over the plantar surface of the feet, the caudal aspect of theintertarsal joint and over the sternum. In addition constant sitting ofthe birds resulted in development of breast "busters". Growth rateswere also depressed. Reversion of litter conditons to dry resulted inrapid healing of most of the lesions with a compensatory recovery ingrowth rate.

INTRODUCTION

Wet litter has recently been shown to be a cause of plantar pododermatitis, scabbyhocks and breast lesions in turkeys (Martland, 1984). The author has also observedsimilar lesions in broiler chickens, especially when grown to "roaster" weights, andin broiler breeder males. The latter were also surveyed in a commercial study whichattributed the condition to wet litter. This resulted in the development of painfulfoot lesions and prevented cocks from mating (D. Butler, personal communication).Harms and Simpson (1975) also described foot pad dermatitis and "breast blisters"in chickens, associated with wet litter. Since this present experiment was completedGreene et al (1985) have described an apparently identical field condition as-sociated with wet litter in Northern Ireland. In addition to severe plantar podo-dermatitis they describe breast lesions as "breast burns", being a dermatitis of thebreast skin rather than the fluid-filled subcutaneous bursae described by McCuneand Dellmann (1968). In either case there is economic loss through carcass condem-nations.

This experiment was designed to study the pathology of plantar pododermatitisand lesions of the skin over the caudal aspect of the intertarsal ("hock") joint andsternum in broiler chickens, and to determine whether wet litter was important intheir pathogenesis. The reversibility of these lesions was also investigated.

Received 29 January 1985Accepted 18 March 1985

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MATERIALS AND METHODS

Two groups of 39 Ross 1 broiler chicks were housed at one-day-old in two pens(3 x 1.1 m2) in the same controlled-environment room. Infra-red brooders wereused for the first 3 weeks with ducted warm air providing background heat. Theywere maintained in continuous bright light for the duration of the experiment.White wood shavings were used as litter at a depth of approximately 5 cm. Com-mercial broiler diets (Nitrovit Ltd., Thirsk, England) were fed ad libitum inaccordance with the manufacturer's recommendations. Water was freely available.

From 24 days of age the litter in one pen (treated group) was spTayed with watertwice weekly to produce wet crusty litter. The litter in the other pen (controlgroup) was kept dry by regular renewal of shavings around the drinker and feeders.At the end of the experiment samples of litter from each group were assessed formoisture content as previously described (Martland, 1984). Litter pH was alsomeasured at various depths using Whatman pH paper.

All the birds were weighed weekly from one-day-old to 6 weeks and at 9 weeks.Their feet were cleaned and examined for evidence of plantar pododermatitis andother skin lesions at approximately weekly intervals from 3 to 9 weeks. Foot lesionseverity was scored on a scale of 0 to 3 as previously used for turkeys (Martland,1984):

Score Lesion0 None1 Small scab(s) <5% pad area2 Larger scabs <25% pad area3 Severe, large scab-filled ulcers

At 5 weeks eight birds from each group were killed. Thin slices of skin were takenfrom the metatarsal pad, hocks and sternum. These were fixed in formal saline,paraffin-embedded, sectioned, stained with haematoxylin and eosin (HE), andexamined histologically.

At 7 weeks 10 birds from each group (five males and five females) were transferredto the opposite groups (i.e. wet-dry transfers and dry-wet transfers).

At 9 weeks all the birds were killed. Skin lesions of the feet, hocks and breast wereobserved; maximum length and width of the breast skin lesions were measured andtheir areas estimated as an oval. The feet of all the birds were removed at the inter-tarsal joint and the plantar surfaces were cleaned and photographed. The photo-graphs were analysed using a modified computer based image analyser ("Imaganbasic", Graphic Information Systems Ltd., Blairgowrie, Scotland) to determine thesize of each foot and the % area affected by gross lesions. The area of footmeasured was restricted to that distal to and including the metatarsal fold (plicametatarsalis) but excluded the claws and accessory digit. Slices of metatarsal pads,hock and breast skin were taken for histological examination.

Statistical analysisStudent's t test was used to compare body weights, mean of left (L) and right (R)plantar foot areas and mean (L & R) % foot area affected by gross lesions for eachof the treatment groups and between sexes within treatment groups. Foot lesionscores, mean (L & R) plantar foot areas and mean (L & R) % foot area affected bygross lesions were analysed using a one sample analysis of variance and their

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Dermatitis in broilers 355

distributions compared using x2 (chi-square) tests. Correlations between final bodyweight on both mean foot area and mean % area affected were assessed using alinear regression.

RESULTS

Effects of treatments on litterThe litter sprayed with water became wet and covered with a layer of caked slimyfaeces after about 1 week of treatment. The appearances were similar in theauthor's experience to those seen around drinkers in commercial broiler sheds. Theuntreated Utter remained dry and friable for the duration of the experiment. Thelitter moisture content at the end of the experiment was 71% for the wet litter and58% for the dry. The pH was 7.0 to 7.5 for wet litter and 8.0 to 8.5 for the dry.

Clinical signsChickens grown on wet litter rapidly became dirty and would sit huddled togetheron the litter. They would move if driven and did not show signs of pain. Thechickens on dry litter remained active and clean. Chickens transferred to wet litterat 7 weeks were indistinguishable from the wet litter group by 8 weeks whereasthose transferred from wet to dry litter rapidly recovered.

Body weightsWithin 1 week of commencement of treatments the birds on wet litter were signifi-cantly reduced in body weight compared with the birds on dry litter (p < 0.05).The reduction in body weight became more significant as the treatment continued(P < 0.01). Separate analysis of male and female body weights at 9 weeks furtherimproved the significance of the body weight reduction (P < 0.001). The birdstransferred from wet to dry litter at 7 weeks improved their weights and were notsignificantly different from the controls at 9 weeks. Conversely the birds transfer-red from dry to wet litter showed a significantly reduced body weight comparedwith the dry litter group (males, P < 0.01, females P < 0.05). The effects of treat-ment on body weight with duration of treatment are summarised in Text-fig.1 andTable 1.

Development of gross lesions and lesion scoresLesions of plantar pododermatitis affected a few birds in both groups before litterspraying commenced but lesion scores were not significantly different. Theselesions were mild, comprising brown-black discoloration of one or two reticulaeof the metatarsal pads. Following litter spraying lesion incidence and severityincreased in the treated group resulting in a scab-filled ulcer of the metatarsal pad.Mean lesion scores also increased rapidly following spraying and were significantlyhigher after 1 week (P < 0.001). As the treatment continued ulcération and scabformation was also seen to affect the digital pads and towards the end of theexperiment ulcération of the interpad spaces also occurred which often resulted inconfluent metatarsal and digital pad lesions (Fig.la). The untreated controls re-mained only mildly affected (Fig.lb).

Lesion scores continued to rise with duration of treatment and after 4 weeks(7 weeks old) all the birds on wet litter had the maximum score of 3 (p < 0.001compared to controls). The mean lesion scores are summarised in Text-fig.2.

Birds transferred from dry to wet litter at 7 weeks of age also rapidly developedlarge ulcers of the metatarsal and digital pads and the interpad skin. After 1 week

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Table 1. Plantar areas of feet, area affected by scabs (%) and body weights of9-week-old broiler chickens. Values are means ± s.e. means.

Littertreatment

Dry

Wet

Wet-Dry

Dry-Wet

Sex

Ma

F

MFMFMF

No. ofbirds

109

1195545

Mean plantararea of foot

(mm2)

2848 ±54.42058+53.6

3344 ±61.2***2452 ±68.9***2986 ± 129.32155 ±87.3*3010±23.8*2497 ±77.7***

Mean areaaffected

by scabs (%)

0.2 ±0.10.3 ±0.1

43.0±3.1***37.0+2.7***

0.4 ± 0.252.1 ±0 .1*

30.1 ±4.7***29.3 ±2 .1***

Mean bodyweight

(g)

3425 ± 6 92683 ± 782913 ±95***2306 ±59***3290+532560 ±532975 ±75**2390 ± 5 1 *

a M = Male, F = Female.

* P < O.OS compared with controls (dry litter)

*• P < 0.01 compared with controls (dry litter)

**• P <C 0.001 compared with controls (dry litter)

3000

Dry litterWet litter

p=<0-05p=<0-01

3 4 5 6Age (weeks)

8 9

Text-fig.1. Mean body weights of broiler chickens grown on wet and dry litterfrom 3 weeks of age.

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Dermatitis in broilers 357

Fig.la. Foot of a 9-week-old broiler chicken grown on wet litter from 3 weeks ofage, showing scab covered ulcers of the metatarsal and digital pads andinterpad spaces of digit 3. Ulcération of the hock skin is also present.

Fig.lb. Foot of a 9-week-old broiler chicken grown on dry litter.

Photomicrograph of the ulcerated hock skin of a 5-week-old broiler grownon wet litter from 3 weeks. Thrombosis of a dermal blood vessel (centre)is apparent close to the edge of the ulcer (left). There is some ballooningdegeneration of the surviving epidermis (right). HE

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Fig.3. Photomicrograph of the breast skin of a 5-week-old broiler chicken grownon wet litter from 3 weeks. The epidermis is ulcerated (left) and coveredwith a scab. The surviving epidermis (right) under-runs the scab but isundergoing ballooning degeneration and is infiltrated with heterophilleukocytes adjacent to the scab. HE

Fig.4. Photomicrograph of the epidermis of the foot pad of a 5-week-old broilergrown on wet litter from 3 weeks of age. Vesicles filled with heterophilleukocytes are present. HE

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Dermatitis in broilers 359

• o Dry litterA A Wet littera----« Wet—-drylitter*- •• Dry—• wet litter

Age (weeks)

Text-fig.2. Mean foot lesion score of broiler chickens grown on wet and dry litterfrom 3 weeks old. At 7 weeks the litter treatments were reversed for10 birds from each group.

lesion scores were significantly higher than controls (P < 0.001) and after 2 weeksall had the maximum score.

Conversely, birds transferred from wet to dry litter quickly showed signs of recov-ery with healing of the ulcers. After 2 weeks many birds had completely recoveredwith regeneration of the digital and metatarsal pads and interpad skin. In somebirds the metatarsal scabs persisted but were smaller and appeared to lie on top ofhealed epidermis. The healed pads were smooth and no longer showed the normalreticular pattern. After 2 weeks lesion scores were not significantly different to thecontrols.

Hock and breast skin lesions appeared in the treated birds 1 week after litter spray-ing. These were initially small lesions but rapidly increased in incidence and severitywith duration of the treatment. After 6 weeks (9 weeks old) the breast lesions werelarge oval scabs caked with litter and faeces. In many of these birds fluid-filledsternal blisters were also found on post mortem examination. The fluid in theseblisters was grey, mucoid and slightly turbid, occasionally tinged with blood or'flecked with small yellow casts of pus. The size and incidence of these lesions issummarised in Table 2.

Birds transferred from dry to wet litter at 7 weeks were also rapidly affected with

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360 M.F. MarÜand

hock and breast lesions and at 9 weeks were indistinguishable from the maintreated group. Birds transferred to dry litter at 7 weeks showed rapid recoveryand by 9 weeks had a reduced incidence of hock and breast lesions. These changesare also summarised in Table 2.

Table 2. Estimated mean area of breast scabs, incidence of breast and "hock"scabs and sternal blisters in 9-week-old broiler chickens on wet anddry litter.

Littertreatment

DryWet

Dry-WetWet-Dry

No. ofbirds

1920

910

Mean (± s.e. mean)area of breast scabs

(mm2)

02056 ±212***2676 ±403***

67± 37

No. withbreastscabs

020

94

No. withsternalblisters

01172

No. with"hock"scabs

720

98

**• P <0 .001 compared with controls (dry litter).

Image analysis of plantar foot areas and lesion areasBoth male and female birds grown on wet litter had significantly larger feet(P < 0.001) than the controls. Birds transferred to wet litter at 7 weeks also hadsignificantly larger feet (males P < 0.05, females P < 0.001). Conversely the malestransferred to dry litter at 7 weeks did not have significantly larger feet than themale controls. The females transferred to dry litter still had significantly largerfeet than the female controls (P < 0.05) but nevertheless had significantly smallerfeet than the females retained on wet litter (P < 0.001). There was a good corre-lation of foot size with final body weight within each treatment group.

The % area of the feet with ulcération and scabs showed a similar pattern. Com-pared with the controls both the wet litter and dry-wet litter groups showed agreatly increased % area of foot affected by lesions (P < 0.001). The feet of malestransferred at 7 weeks to dry litter had almost completely healed and the % areaaffected was not significantly different. The females from the wet-dry group stillhad residual lesions which were significantly larger than the controls (P < 0.05),however, they were highly significantly smaller than the females retained on wetlitter (P < 0.001). Within each treatment group sex of bird had no significantinfluence on % area of foot affected. Nor was there any correlation with final bodyweight. These results are summarised in Table 1.

Histopathology of foot, hock and breast lesionsThe skin lesions of the breasts, hocks and foot pads of birds grown on wet litterwere essentially similar, being extensive ulcération of the epidermis. The ulcerswere filled with a thick cellular scab which at the base bordered onto inflameddermis with massive infiltrations of heterophil leukocytes. A palisade of giantcells was commonly present at the scab/dermal margin, especially in the olderbirds. Beneath this the dermis was thickened with granulation tissue. This zone offibrosis was thicker in the older birds. Frequently the dermal capillaries closest tothe base of the ulcer were thrombosed and occluded (Fig.2). In some birds thethrombosed vessels were incorporated into the necrotic scab. At the edges of theulcer the epidermis was thickened and under-ran the scab (Fig.3). The Stratum

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Dermatitis in broilers 361

comeum at this point was frequently split into laminae with coccal bacteria presentin the fissures. Beneath this the Stratum transitivum was infiltrated with heterophilleukocytes and also undergoing ballooning degeneration, resulting in vesiculationof the epidermis (Fig.4). Peripheral to this the epidermis was still thickened withunderlying dermal inflammation. The S. comeum was thickened and hyperkeratoticwith areas of parakeratosis and imperfect keratinisation. In the hock lesions the in-flammatory reaction did not extend into the underlying tendon sheaths. Birds withsternal blisters showed cavity formation in dense dermal granulation tissue. Thecavities were lined with small polygonal cells and contained numerous finger-likeprojections of granulation tissue.

Skin lesions in birds transferred from dry to wet litter were indistinguishable fromthose maintained on wet litter throughout.

The foot pads of birds transferred to dry litter at 7 weeks still showed areas ofepidermal inflammation and ulcération at 9 weeks but these less extensively thanthat of the birds maintained on wet litter. The dermis contained more fibroustissue than the corresponding dry litter controls. Where the epidermis had regen-erated over the crown of the metatarsal pads it produced a flat sheet lackingpapillary scales. The hocks still had large scab covered ulcers, intraepithelial inflam-mation, dermal capillary thrombosis and extensive granulation tissue. Ameliorationof the sternal dermatitis was apparent in some but others still had severe ulcérationof the epidermis with overlying scab formation. Dermal perivascular cuffs of lym-phocytes and thick granulation tissue were apparent even in those birds withhealed epidermis.

The control birds, grown entirely on dry litter, had very few foot pad lesions at5 weeks old. These were small infiltrations of the epidermis with heterophil leuko-cytes and occasional dermal lymphoid foci. The majority of foot pads examinedhad no lesions. At 9 weeks occasional small ulcers could be found. Some birdshad scab material attached to an intact Stratum germinativum. Mild hyperkeratosiswas present in several feet on the crown of the metatarsal pads. Hock and breastskin lesions were minimal in control birds at both ages examined.

DISCUSSION

Wet litter produced plantar pododermatitis in commercial broiler chickens com-parable to that produced in turkeys (Martland, 1984) but differing in severalrespects. The metatarsal and digital pads and interpad spaces became ulcerated inchickens whereas only the pads were affected in turkeys. Thrombosis of the dermalvessels was a prominent feature of chickens with plantar pododermatitis but wasnot seen in turkeys. However, Schmidt and Lüders (1976) described thrombosisof dermal vessels in turkeys with pododermatitis. Vesiculation of the epidermis wasalso more prominent in chickens.

Harms and Simpson (1975) also described plantar pododermatitis associated withbreast blisters in broiler chickens. They suggested that the foot pad lesion causedthe birds to sit on their breasts for long periods resulting in the development ofbreast and hock lesions. This was also observed in this study. This is probably dueto contact with the litter and litter-derived irritants as suggested by Greene et al.(1984) who described identical lesions in field cases. However, prolonged sittingalso resulted in the development of breast "blisters" in addition to breast "burns",

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362 M.F. MarÜand

possibly due to pressure.

There was no indication in this study that sex or bodyweight influenced the sever-ity of lesions in birds grown on wet litter. Harms and Simpson (1975) reportedthat foot pad lesions were more severe in heavier birds and rarely seen in females.They attributed the latter to higher biotin requirements of male broilers as theyalso found that biotin deficiency produced similar gross and histological footlesions. Schmidt and Lüders (1976) also observed a high incidence of plantarpododermatitis in male but not female turkeys, attributing this to the higherweight of the males. However, Harms et al. (1977) found that wet litter increasedseverity of foot pad dermatitis and that female broilers were more severely affectedthan males. They found that biotin deficiency exacerbated the lesions on wet litterand also resulted in lesions in birds on dry litter. Supplementation of the diet withbiotin corrected the latter but only produced slight amelioration of the lesions seenin birds grown on wet litter.

Harms and Simpson (1977) found that turkey poults behaved similarly — wet litterand/or biotin deficiency produced foot pad ulcération which could be corrected ondry and ameliorated on wet litter by biotin supplementation.

In this experiment commercial broiler diets were fed and these were believed tobe adequate in biotin. The absence of all but minor skin lesions in the chickensgrown on dry litter would appear to support this assumption. Wet litter appearedto be the only factor resulting in ulcération of the feet and subsequently hocksand breast.

Transfer of 7-week-old affected chickens to dry litter resulted in rapid resolutionof footpad and breast skin lesions in both males and females. However, the feetof the females appeared to heal more slowly than those of males and had smallresidual lesions on the pads after 2 weeks. Hock scabs were more intractable andmany chickens still had quite large scabs. Breast scabs and blisters also persisted ina few birds. Rapid healing of lesions when litter became drier was also observed ina field study of commercial broilers by Greene etal. (1985).

Depression of growth rate was seen in the affected birds in this experiment. Aswith turkeys (Martland, 1984) this could be due to pain-induced inappetance.Transfer of affected birds to dry litter at 7 weeks resulted not just in rapid healingof the lesion but also in a compensatory increase in growth rate.

The pathogenesis of the foot pad lesions is still obscure but this study confirmsthat wet litter is a major contributory factor. Ammonia (or other unspecifiedcorrosive substances) have been suggested as a litter irritant which could result indermatitis (Schmidt and Lüders, 1976; Nairn and Watson, 1972) but in this experi-ment the litter pH was more alkaline in the dry litter group. It has also beensuggested that adhesion of faeces to the feet will produce plantar pododermatitisin poults grown on wire (Jensen et al., 1970), possibly due to irritation by micro-organisms. It appears that contact with faecal products is required. Contactdermatitis of breast and hock skin occurs secondarily to the birds sitting on thelitter as proposed by Greene et al. (1985). Breast blisters have already been shownto be induced by prolonged pressure from sitting (McCune and Delmann, 1968).

Wet litter is thus likely to be a serious cause of economic loss to the broiler growerthrough carcass condemnations and poor feed conversion rates. This can be pre-

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Dermatitis in broilers 363

vented by growing chickens on dry litter and promptly replacing areas of dampnessthat may appear.

A cknowledgemen tsThanks to Dr. AM. Lawn for his image analysis programme "TABDAT" and toMr. P. Martin for painstakingly tracing foot images.

REFERENCES

Greene, J.A., McCracken, R.M. and Evans, R.T. (1985). A contact dermatitis of broilers -clincial and pathological findings. Avian Pathology, 14: 23-38.

Harms, R.H., Damron, B.L. and Simpson, C.F. (1977). Effect of wet litter and supplementalbiotin and/or whey on the production of foot pad dermatitis in broilers. Poultry Science,56: 291-296.

Harms, R.H. and Simpson, C.F. (1975). Biotin deficiency as a possible cause of swelling andulceration of foot pads. Poultry Science, 54: 1711-1713.

Harms, R.H. and Simpson, C.F. (1977). Influence of wet litter and supplemental biotin on footpad dermatitis in turkey poults. Poultry Science, 56: 2009-2012.

Jensen, L.S., Martinson, RM. and Schumaier, G. (1970). A foot pad dermatitis in turkeypoults associated with soybean meal. Poultry Science, 49: 76-82.

Martland, M.F. (1984). Wet litter as a cause of plantar pododermatitis, leading to foot ulcera-tion and lameness in fattening turkeys. Avian Pathology, 13: 241-252.

McCune, E.L. and Dellmann, H.D. (1968). Developmental origin and structural characters of"Breast Blisters" in chickens. Poultry Science, 47: 852-858.

Nairn, M.E. and Watson, A.RA. (1972). Leg weakness of poultry - a clinical and pathologicalcharacterisation. Australian Veterinary Journal, 48: 645-656.

Schmidt, von V. and Lüders, H. (1976). Zehen-und Sohlen-ballengeschwüre bei Mastputen.Berliner und Münchener Tierärztliche Wochenschrift, 89: 47-50.

RESUME

Dermatite ulcérative chez le poulet de chair:effet des litières humides

Des litières humides induisent une sévère ulcération de la peau de poulets de chairau niveau de la surface plantaire des doigts, la partie postérieure de l'articulationintertarsienne et le sternum. De plus les oiseaux qui sont accroupis constammentdéveloppent des ampoules du brechet. La croissance est diminuée. L'améliorationde la qualité de la litière se traduit par une guérison rapide de la plupart des lésionsavec une récupération du poids.

ZUSAMMENFASSUNG

Ulcerative Dermatitis bei Broilern. Die Auswirkungeneiner feuchten Einstreu

Feuchte Einstreu veranlaβte schwere Hautulcerationen auf der Plantar Oberflächeder Füße, der kaudalen Seite der Intertarsalgelenke und über dem Sternum. Zusätz-lich führte die ständig sitzende Stellung der Tiere zur Entstehung von Brustblasen.Die Wachstumrate war herabgesetzt. Durch eine Berichtigung der Einstreuver-hältnisse wurde eine rasche Abheilung der Veränderungen und eine kompensa-torische Erhöhung der Wachstumsrate erreicht.

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364 MJ. Marüand

RESUMEN

Dermatitis ulcerativa en pollos de engorda:efectos en camas humedas

Una cama húmeda provocó ulceración severa de la piel de pollos de engorda comer-ciales, en la superficie plantar de las extremidades inferiores, en la parte caudal dela articulación intertarsal y en el esternón.El contacto constante de las aves con la cama húmeda favoreció el desarrollo de"ampollas" en la pechuga. Asimismo, las tasas de crecimiento se redujeron.

La reversión de las condiciones de la cama y el secado de la misma condujo a unarápida cicatrización de la mayoría de las lesiones y a una recuperación compensa-toria de la tasa de crecimiento.

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