4-H Embryology

An Overview

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Let’s begin with eggs.

EACH YEAR IN THE U.S. COMMERCIALLAYING HENS PRODUCE BILLIONS OF

TABLE EGGS FOR US TO EATBECAUSE THEY ARE VERY NUTRITIOUS

…HOWEVER…IN NATURE

THE EGG IS NOT FOR EATINGIT IS FOR REPRODUCTION

ANDONLY FERTILE EGGS WILL HATCH

• Fertile eggs come from special farms called breeder farms where roosters and hens live together

and these eggs are incubated to produce chicks.

•The eggs you buy at the grocery store are grown at “hen only” farms and they are not fertile so they will

not hatch when they are incubated.

Let’s begin with eggs.

How does an egg work?THE EGG HAS MANY PARTS AND

EACH PART HAS AN IMPORTANT FUNCTIONDURING CHICK DEVELOPMENT

…FOR INSTANCE…THE SHELL PROVIDES

PROTECTIONGASEOUS EXCHANGE

(O2 ENTERS AND CO2 LEAVES)CALCIUM FOR BONES

THE YOLK PROVIDESPROTEIN

FAT (FOR ENERGY)VITAMINS AND MINERALS

YOLK

THE ALBUMEN PROVIDESPROTEIN

VITAMINS AND MINERALS

THE CHALAZAKEEPS THE YOLK IN

THE CENTER OF THE EGG

THE GERMINAL DISCIS WHERE FERTILIZATION

OCCURS AND THECHICK BEGINS DEVELOPING

• CLEAN FERTILE EGGS WILL BE PLACED IN

THE INCUBATOR

Startup day!

• MAKE SURE THE INCUBATOR IS FUNCTIONING PROPERLY AND READY FOR THE EGGS

• provides and maintains a favorable environment for hatching fertile eggs.

• replaces the hen.

• must function properly and should be checked daily.

An incubator…..

Important factors to successful incubation are:

• Temperature– Between 98-103º F

• Ventilation– Clean fresh air must flow through the incubator

• Turning the eggs– Eggs must be turned carefully 3 times each day.

Some incubators have an automatic egg turner.

• Humidity (water)– There must be moisture to keep the chick

developing normally and prevent dehydration.

• Candling is the process of looking inside of an egg without cracking it to see if the chick is developing.

A bright light is used to “candle” the egg.

Candling eggs

• Notice the blood vessels. This is the embryo growing and eventually it will be developing very

quickly and fill up the entire inside of the egg.

Candling Day 3

Notice that the entire embryo is growing bigger and is developing all of its body systems.

Candling Day 7

• Most chicks hatch on day 21, but sometimes hatching begins a day or two earlier or later depending on the conditions during incubation such as temperature,

humidity, etc.

• Be patient when hatching begins because it may take several hours for a chick to exit the shell.

• It is best not to help the chicks hatch•The struggle to hatch is necessary

for survival.

Hatching time!

Hatching start to finish.

Chicks hatching and drying in the

incubator.

Hatching

• Chicks stay in the incubator until they are dry and fluffy.

• It may take several hours for the chicks to dry.

• Once they are dry, place them in the brooder.

• Teach them to drink water by placing each chick’s beak in the water source and then place them next to the feed source so they will find it quickly.

The chicks have hatched,

now what ???

• A pen for chicks that provides protection, heat, feed and water and space to move around.

• Absorbent bedding material is required so the chicks can walk on it and scratch in it. Wood

shavings, paper towels, shredded newspaper work great!

• A heat lamp provides the chicks light and warmth.

What is a brooder?

• A pre-mixed commercial chick starter. This may be purchased at a local feed store. Pet stores usually do not

sell this type of feed. Grit is not necessary at this age.

• DO NOT feed “scratch feed” or ground corn because the chicks require more protein, vitamins and minerals

than are in these feeds.

What should the chicks be fed ?

• Change out daily–Bedding

–Water

–Food

Keep your brooder CLEAN!!

Happy Hatching!

Connelly, R., Mores, C. & Simonne, A. (2009). What are the risks of contracting diseases associated with chickens? (EDIS ENY-724). Gainesville. University of Florida: Entomology and Nematology Dept.

DeCubellis, C. (2007). Care of baby chicks (EDIS AN-170). Gainesville. University of Florida: Animal Science Dept.

National 4-H Curriculum (2008). Hatching Classroom Projects: Helper’s guide beginner grades 2-5 (BU-07595). Washington, DC: National 4-H Council.

National 4-H Curriculum (2001). Experiments in poultry science: Helper’s guide advanced grades 6-8 (BU-07596). Washington, DC: National 4-H Council.

References

4-H Embryology Working Group Team Members

Andy Toelle, Extension Agent Duval County

Lori Wiggins, 4-H Agent Taylor County

Chris DeCubellis, 4-H Agent Gilchrest County

Dr Sandra Tenbroeck, Associate Professor, Animal Science

Dr Richard Miles, Professor, Animal Science

This program was made possible by a University of Florida Enhancement Grant