INDUCED MOLTING IN MODERN POULTRY INDUSTRY AND ITS FUTURE SCOPE

Authors: Dr. Muhammad Yousaf, Assistant Professor, Institute of Animal Sciences, University of Agriculture, Faisalabad, Pakistan.

Cell: 03007980720 E-Mail: muhammad.yousaff@yahoo.com

Dr. Abdul Chaudhry, Lecturer in Animal Science & NutritionSchool of Agriculture, Food and Rural Development (SAFRD), Agriculture

Building, NE1 7RU, Newcastle University, Newcastle upon Tyne, UK

E-mail: abdul.chaudhry@ncl.ac.uk

Molting

Molting in avian species is defined as the periodic shedding and replacement of old

feathers. Molting takes place in many animal species like birds, insects, lizard, scorpion, snakes,

elephant seals etc. After molting reproductive activity is resumed, birds are with well looking

features, appealing to their mates, produces more eggs with higher weight. In avian species

seasonal feather molting is initiated and coincides with eggs incubation and brooding of chicks.

Very little feed and water is consumed during incubation period due to which weight reduces,

regression of reproductive organs takes place with renewal of feathers. The birds have ability to

tolerate fasting for longer periods, reproductive organs regression and replacement of feathers.

Molting is a natural phenomenon in the birds where

Feed intake is reducesProduction ceasesOld feathers replaced with new onesWeight reducesFat reserves mobilizesOrgans weight reducesOvary and oviduct rejuvenates

Induced molting in chickens dates back to early nineteenth century. The scientists

investigated different methods for molt induction due to which this practice gained popularity

during 1930s. However, most of the egg producers in the California adopted induced molting in

1950s. The practice of molting continued to increase as indicated by an increase in the number of

research papers being published in 1960s and 1970s. Similarly, induced molting spread in most of

egg producing regions of world with the passage of time as a tool to rejuvenate the spent hens.

Usually, poultry flocks produce eggs for a laying cycle of 1 year duration and then are

sold. Egg production is relatively at low level towards the end of laying cycle, interior and

exterior egg quality are also poorer, particularly if end of the lay coincides with hot weather.

Small eggs are laid at start of egg production, which reduces net income of farmers. It is

estimated that more than 75% of all flocks are molted in USA as a regular replacement program.

Following induced molting birds return to full feed, a new plumage develops and the

birds resume egg production at a higher rate with better egg quality. Induced molting extends the

productive life of commercial chicken flocks and results in substantial reduction in the number of

chickens needed to produce the nation's egg supply. Induced molting also has a positive impact

on the environment through reduction of waste and natural resources needed for growing more

birds for egg production.

Molting is triggered by lowered reproductive activity and thyroid play important role for

onset of molt. During induced molting first T4 level increases and then T3. In natural molting

ovary became atretic in the autumn which decreases oestrogen release thus results in

discontinuation of existing suppressed activation of feather papillae. Feather papillae are

activated by thyroxin/progesterone for formation of an underlying new feather that ultimately

expelled the old feather.

Importance and Implication of Induced Molting

In Poultry Industry, hens are molted for economical production in modern day poultry

operations. Too many expenses are incurred on rearing the pullets (Rs 500) / breeder chicks (Rs.

1300) up to start of egg production. Foreign exchange is also saved when molting is practiced

(less layer breeder imported). In past and to some extent present day, hens after one year egg

production were sold as meat purpose. Nowadays there is increasing trend to keep in cages in

environment controlled or semi environment controlled housing in million numbers. In near

future it is expected that most of the layer flocks will be kept in cages in Pakistan as globally,

90% layer flocks are kept in cages. In modern day layers farming, hens are kept for 2-3 years,

highlighting the practical application of one or two cycle molting programs. No doubt, the

research in layers sector with future vision is on the way to have persistence lay for a longer

periods (500 eggs in 700 days) which show somewhat less application of induced molting. At

present, in USA 75-80% layer flocks are molted. However, in Pakistan, almost all the layer

breeder/parent flocks are molted once or twice for economical production of chicks and earns

more profit. There is increasing trend regarding induce molting in layer flocks in Pakistan

especially in caged hens. In layer breeders chick cost during first production cycle is about Rs

43-45 while molted flock chick cost is Rs. 35 or even less. Ultimately less expenditures are

incurred to produce chicks from a molted flock with added benefit of large size hicks. It is worth

mentioning that broiler breeder flocks are also molted in Pakistan.

Induced molting improves post-molt performance of laying hens when compared to the

pre-molt performance. Salient improvements are increased egg production, improved exterior

egg quality parameters like bigger egg size, improved shell quality, internal egg quality. There is

marked increase in interior egg quality as measured by Haugh unit Score. Induced molting

decreases egg breakage, mortality and culling.

Most significant difference in performance between egg production cycles is for egg

weight. Egg weight during first cycle (1-10 weeks) averaged only 52.3 g and remains below 60 g

per egg until week 20 of lay while during second and third cycles egg weight is 63.4 g. Under

right economic conditions, the economically useful life of a laying flock may be extended from

less than 80 weeks to 110 weeks or even to 140 weeks through judicious use of molting process.

Induced Molting and Planning for More Profit

Main objective of induced molting is less stress, low mortality, less expensive, precisely

planned according to the condition of the bird, proper duration, better management, more

production and ultimately more profit from the molted hens in the subsequent production cycle.

According to the author opinion to fetch more profit in Pakistan induced molting be

planned during July-August for a period of 6-8 weeks. In postmolt period hens will reach their

peak during September and farmer can have five months better production from October to

February subject to provision of 6-8 weeks molting period. Mostly rates from October –February

are better for the table eggs therefore induced molting will be beneficial during this period.

However, farmers can plan according to placement of flock and marketing conditions.

No doubt hens are molted for better egg production, improved eggshell quality and more

profit round the globe. Mostly layer breeder, caged layer and layer in conventional houses are

molted frequently in Pakistan. In near future maximum layers will be shifted into cage system

accompanied with environment controlled condition. On overall basis more expenses are

incurred for rearing the pullets up to maturity while expenses on induced molting are very less.

However, broiler breeder can be molted with a molting during of 10-12 weeks.

Induced Molting Methods

Flock should be molted in such a manner which ensures hen’s well being or welfare

during induced molting. Short molts will not result in long egg production periods. On the other

hand farmers are molting their flocks for one month duration only and are expecting/claiming

very good production which is beyond imagination. Main concern of induced molting is weight

reduction, appropriate rest period to hen’s reproductive system and feather replacement. Induced

molting is not only to off feed hens but it requires sound technical input starting from selection

of birds up to the completion of production cycle..

Feed deprivation method is most widely used method for induced moulting of chickens

but it is unacceptable on hen welfare grounds because of high stress, mortality and incidence of

Salmonella entritidis. Moulting can be induced by reduced photoperiod, feed restriction, diets

containing minerals zinc, copper, aluminium, sodium and potassium iodide, hormones such as

thyroxin and progesterone. Thyroactive proteins, fibrous feeds such as alfalfa and

oligosaccharide have been investigated by the scientists to increase post-moult production

performance of hens. Recently, concerns for the well-being of the hens during an induced molt

have been voiced by animal welfare groups who claim that feed withdrawal method is cruel,

inhumane and have food safety concerns. Therefore, since the year 2000, research has been

focused on using non-feed-withdrawal molting programs. There are many effective non-fast

methods that can be used to induce a molt including low-sodium, high-zinc, high-corn, high-

wheat, oral thyroxin, ad libitum alfalfa and low-calorie diets.

For an example North Carolina Molting Program is very popular, was developed at NorthCarolina State University. This program includes a pre-molt period of 7 days when artificial lights are turned on during the night to give the flock a 24-hour day before feed is removed. This procedure allows the manager to subject the flock to a larger reduction of light at the same time the feed is withheld. On day one of the molt, artificial lights are removed from flocks housed in open-housing and reduced to 10 hours for the first 14 day in flocks housed in controlled-light housing. This is gradually stepped up to 15.5 hours by 28 days. When the target weight reduction is reached (or on the 15th day), the flock is returned to full feed (a 17% protein, 3.7% calcium diet). Lighting is stepped up from the 28 th through the 49th day from 15.5 to 16.5 hours day. It is advised that house temperatures be maintained at 800 P (17 °C) during the feed removal period until the target weight is attained. North Carolina method places major emphasis on body weight

reduction and suggests that weight losses should be 30% for 1.64-kg (Commercial Chicken Meat and Egg Production).

Salient Practical Aspects of Induced Molting

Mostly poultry farmers own their flock but some farmers purchase hens for molting.

What so ever the source is, flock should be healthy (disease free, no lices or internal worms).

Preferred age for molting is 55-65 weeks. However, farmer can decide according to their plans,

facilities and market conditions. It is advisable to have induced molting practice during July-

August and fetching better egg prices from October to February in Pakistan.

Before starting induced molting of the poultry flock there is premolt period. It is just like

you are planning to have a long journey on your car: you check the water in battery plus radiator,

mobile oil, tyre air pressure, petrol and filter. After wards you select most appropriate route with

minimum mileage, safe, cost effective and time saving. For induced molting check flock source,

body weight, general health condition, ecto/endoparsites and disease symptoms if any. Weak,

injured, diseased, low weight birds which will be unable to withstand induced molting procedure

must be isolated and culled from the flock. Anti biotic therapy along with due vaccination must

be practiced. Each and every point needs to be addressed properly for effective induced molting.

At the start of molting period carefully count birds and one should have actual figures in

the respective pens or cages. Misleading figures (bird count) will affect your efforts and

resources. Proper and planned weekly weighing is recommended. On litter floor system sites be

designated in the respective pens from where birds will be weighed in succeeding weeks until the

flock is sold out. It is recommended that all the birds should be weighed being gathered during

weighing at a particular site. Similarly, in cage system, cages be marked to weigh the birds and

to note any decrease/ increase in their body weight while molting or during production period.

Molting period success will solely depend on body weight monitoring and feed

adjustments. Main theme is to reduce the weight of the birds (20-30% or even more in some

cases) and then actual target/goal of this molting is to provide rest period during which the

reproductive system of is rejuvenated. Recommended induced molting duration for layers and

layer breeder flocks is 6-8 weeks while in broiler breeder 9-12 weeks.

Farmers are in favour of fast molting program (one month duration) meaning one starts

molting at the beginning of month and at the end of month birds are again in lay. Is it sensible,

practicable, profit earning and expecting longer production period ? Nothing of these can be

achieved by fast molting program. In fast molting program, the birds neither reach target body

weight reduction nor feather replacement actually starts at a required intensity. Here is the

critical control point to have better production for a longer period, if proper rest period is given

to the flock. I have shared experience with poultry farmers who used to molt their flocks with

complaints and requiring guidance for effective induced molting strategies and better production

performance. How they can fetch best results as they confess that they are using fast molting

program. It is worth noting that during induced molting of flocks, farmers provide less space,

number of feeders are not as per recommendation, too much competition for feed during feeding,

body weight variation, more stress, ventilation problem and higher mortality rates. In well

monitored molting, when target body weight reduction is achieved maintenance diet is provided

to sustain this weight during rest period. Oviduct and ovary are rejuvenated (new cells are

formed) in this rest period. Longer the rest period more persistence egg laying.

Finally, according to author opinion feed withdrawal where permissible be practiced first

for 3 to 10 days depending on the season (< days in summer and > days in winter) along with

two weeks mineral supplementation period and then normal maintenance diet during the rest

period. Feed withdrawal period will ensure rapid weight reduction, minerals will play their role

in induced molting and proper rest period will ensure required rejuvenation of reproductive

organs. Countries where feed withdrawal molting is not permitted non feed withdrawal molting

techniques are available for induced molting. Light duration be reduced as per daylength in

conventional system while in cage system 08 hours light with 10 Lux intensity is recommended.

During molting period egg production continues even up to 10 to 12 days, therefore, feeding

calcium source at this stage will ensure proper egg shell quality, intact eggs and calcium will not

be mobilized from the hen’s body reserves.

More economical diets can be prepared for cost effective induced molting. Metionine

levels can be increased when there is rapid shedding of feathers. Persistent monitoring is a key to

successful induced molting of poultry flocks. Induced molting is practiced keeping in view the

condition of the bird during molting period. Changes can be made as and when needed.

Scientific, Applied and Economical Induced Molting Techniques

The author has developed non feed withdrawal induced molting techniques at University

of Agriculture, Faisalabad which are being practiced at national and international level with

excellent results. Main features of these techniques are less mortality rate; less expenditure

during molting period, less stress, medium body weight reduction during molting, better post

molt egg production and more profit margins. During induced molting flocks are properly

monitored which results in more egg production, improved eggshell quality, large size of the

eggs, less mortality. Technical guidance is available to molt flocks by feed withdrawal, non feed

withdrawal, minerals supplementation, hormonal therapy.

The author has successfully molted flocks of layer, layer breeder and broiler breeder of

various companies in Pakistan and also on international levels. The author has successfully

completed molting projects during M.Sc. (Hons.), Ph.D, and psodoctoral studies at United

Kingdom funded by Higher Education Commission Pakistan, Pakistan Science Foundation and

Yorkshire Agriculture Society UK. Recently three students have completed research trials on

various aspects of induced molting in 2016. Poultry farmers, big poultry units owners,

production controllers, farm managers, progressive farmers, technical people are consulting the

author regarding various aspects of induced molting from time to time. It is worth mentioning

that University of Agriculture Faisalabad (Department of Poultry Science) is pioneer in

providing the technical guidance regarding induced molting to the poultry industry

Photographs showing Induced molting of Layer Breeder Flock in Pakistan

Layer breeder hen showing regressed comb during molting process

A layer breeder hens exhibiting shining comb during second production cycle

Regressed ovary/oviduct of breeder hens during induced molting

A non molted layer breeder hen showing functional ovary and oviduct

Newly emerging primary feathers Extensive molting process in layer breeder hens

Primary feathers mostly replaced Replaced primary feathers with an emerging one