The Chicken Digestive System
Small intestine
Aids in digestion and nutrient absorption. Made
up of the duodenum, jejunum, and ileum.
The chicken digestive tract is like other monogastric (single
The largest glandular organ in the body. Aids in
Liver
stomach) animals such as pigs, horses, and dogs. The most notable
differences in their GI tract are lack of teeth, crop, proventriculus,
the metabolism of carbohydrates, fats, proteins,
gizzard (ventriculus) ceca and cloaca.
and sugars.
Bacterial action which helps breakdown
Ceca
undigested food passing through the intestine.
Labelled diagram of the chicken
The ceca turn into the large intestine, which
digestive system
connects with the cloaca.
Large Intestine
To absorb water, dry out indigestible foods and
eliminate waste products.
Cloaca
Where digestive, urinary, and reproductive
systems meet.
The external opening of the cloaca that passes
Vent
waste to the outside.
A Ruminant Digestive System
RUMINANTS:
The process of digestion ~
1. All herbivores (plant eating mammals) are called ruminants.
Chickens do not have teeth. Therefore, mastication does not occur.
2. They chew the cud to breakdown plant matter and stimulate
They simply swallow their food whole; it then passes down the
digestion.
oesophagus and into the crop where food is stored until it is ready to
3. The stomach is divided into four chambers – rumen,
be passed into the proventriculus. This organ is the glandular
reticulum, omasum, and abomasum.
stomach where food is exposed to gastric juices, hydrochloric acid,
Ruminants are animals with four-part stomachs which allows them
and digestive enzymes. The gizzard is an organ with thick, muscular
to chew food more than once (regurgitate). Examples of these
walls that grind feedstuff into smaller pieces which makes digestion
animals include sheep, goats and cattle which chew their cud
easier.
(ruminate). Cud is undigested vegetation which has been swallowed
From the gizzard, food travels to the small intestine which consists
and then ‘regurgitated’ back into the mouth for chewing. When it is
of the duodenum, jejunum, and ileum. The duodenum is responsible
swallowed again, the cud passes into the digestive system.
for digesting proteins, fats, starch, and sugar. As such, the jejunum
and ileum are primary sites for absorbing these nutrients. Undigested
food enters the ceca which is a vast house for bacteria, yeast,
protozoa, and fungi capable of digesting structural carbohydrates
such as cellulose and Fiber. From the ceca food moves into the colon
for water absorption. At this point, undigested food passes through
the cloaca and exits the chicken.
Parts of the chicken digestive system
and function~
Parts
Beak
Function
The process of digestion ~
Where food is picked up (pecking) and broken
Through the action of rumination, ruminants ferment the food,
up until able to swallow.
Oesophagus
Transports food from the beak to the crop.
Crop
A pouch in the oesophagus used to store food
regurgitate, and chew their food before the main digestion process.
1. Ruminants quickly swallow the food and store it in the
rumen.
temporarily before passing into the
2. Once the rumen is filled, food passes into the second
proventriculus.
Proventriculus
Gizzard
chamber, (reticulum).
The organ where food is broken down by gastric
3. In the reticulum, digestive juices partially digest the food.
juices, digestive enzymes, and HCL.
4.
The muscular part of the stomach that uses grit
5. Now when mammals are resting, they bring the cud back up
to grind grains and Fiber in smaller pieces.
Partially digested food is called cud.
into the mouth for regurgitation.
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6. After cud is chewed, food is passed to the omasum and the
(one yolk) has matured it is released from the ovary into the oviduct
abomasum.
and its termed ovulation.
7. Symbiotic bacteria in the caecum brings about the complete
digestion of cellulose.
Processes of Rumination ~
Part of
Length of
Time spent
oviduct
part
there
Infundibulum 2 inches
15 min
Function of part
Picks up the yolk and
Rumination is a complex process involving regurgitation,
deposits it into the
remastication, insalivation, and deglutition.
magnum.
Magnum
Regurgitation – is the process by which partially digested feed
13 inches
3 hours
Albumen is produced and
returns from the stomach to the rumen to be remasticated.
surrounds the yolk which
Remastication – when the regurgitated feed is chewed again and
forms the chalazae which
break into smaller pieces.
hold the yolk in a central
Insalivation – is the process in which saliva is produced, mixed with
position.
Isthmus
remasticated food to aid in digestion.
4 inches
1.25 hours
Two shell membranes are
placed around the egg.
Deglutition – when remasticated food is mixed with saliva,
swallowed, and passed to the rest of the digestive system to
Uterus (Shell
complete digestion.
Gland)
4.2 inches
20.75 hours
The shell, formed mainly
of calcium carbonate, is
deposited on the outer cell
membrane.
Four compartments and functions
Vagina
4 inches
1-10 minutes
The egg only stays here for
Structure
Function
Rumen
Storage of ingested food; addition
a short time during which it
of saliva to food. Digestion of
is rotated through 180
cellulose by enzymes secreted by
degrees so that it is laid at
bacteria and protozoa.
the large end first.
Reticulum
Omasum
Vent/Cloaca
Separation of larger pieces of food
4 inches
The completed egg is
for regurgitation to the mouth via
expelled through this
the oesophagus.
opening.
Storage of liquified food, muscular
Structure of the Egg ~
contractions grind food into
smaller pieces. Water and finer
particles move to the abomasum.
Abomasum
Storage of liquified food; Chemical
digestion of food by enzymes
(proteins).
The Reproductive Tract of a Hen ~
The egg structure is composed of shell, membrane, Air cell, egg
white, egg yolk, and chalaza. The egg white forms 2/3rd of the whole
whereas egg yolk covers only 1/3rd of the whole egg. The eggshell is
hard and brittle and is either white or brown, it is composed of
calcium, magnesium carbonate, and calcium phosphate.
The Egg has:

Two shell membrane which protects the inner parts against
bacterial invasion.

The reproductive tract of a hen is made up of two parts: the ovary
Albumen (egg white) made up of proteins, minerals, water
and for developing an embryo.
and the oviduct. Ova (yolks) develop in the ovary. When an ovum
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
The air cell serves as a tiny shock absorber during early
Folder – dried feedstuffs, such as hay, straw and chaff are used
embryonic development.
when forages are unavailable: can also include green chopped

The chalaza holds the yolk in the centre of the egg.
feedstuffs, such as corn stalks, elephant grass and kudzu.

The yolk is a source of food for the embryo and contains fat
Silage – pasture grasses, legumes and other crops conserved and
in the egg.
stored in silos.
The germinal disc is where the female’s genetic material is
Rabbit Production ~
found.
Male
Female
Young
The shell of an egg contributes to protection, respiration, and
Buck
Doe
Kitten


water exchange.

Reasons for raising rabbits:
The Vitelline membrane (VM) protects and vives shape to

Food

Clothes
Incubation of eggs ~

Economic benefits
Layer birds produce fertile eggs for hatching. Eggs selected for

Pet/Comfort
the egg yolk and separates it from the egg white.
Breeds of Rabbits:
hatching should be cleaned, of a good size, and shape. These can be
hatched naturally by a broody hen or can be hatched artificially in an

New Zealand White
incubator. Eggs take 21 days to hatch. The egg in the incubator must

New Zealand Red
also have good circulation of air and a source of moisture to prevent

Chinchillas
them from drying out.

Flemish Giant

Californian White
Candling Eggs ~
Mating  Kindling  Weaning
In the process of candling, Eggs being incubated are carefully
Signs of Heat:
examined with the use of a candle to find out whether a dark area is

Slimey discharge from Vulva.
seen it means that an embryo is present.

Swelling of the Vulva

Making a lot of noise

Humping other animals
Feed Conversion Ratio ~
Feed Conversion Ratio (FCR) is efficiency with which the bodies of
Mating – The doe will mate with the buck once she is in heat which
livestock convert animal feed into the desired output (weight).
means when she has produced eggs ready to be fertilized.
𝑡ℎ𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑓𝑒𝑒𝑑 𝑖𝑛𝑡𝑎𝑘𝑒
Pregnancy – The gestation period for rabbits’ is 31 days.
FCR formula = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑔𝑎𝑖𝑛𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑎𝑛𝑖𝑚𝑎𝑙
Kindling – The process of giving birth to kittens.
Importance of FCR

Helps control expenditure on feed

Helps in identifying animals which are efficient feed
Weaning – When kittens gradually give up milk for solid feed, this is
usually after 8 weeks.
Digestion in rabbits
converters.

A rabbit is an herbivore with a simple stomach. Rabbits are fed on:
Selection of classes and breeds of animals that have low feed

conversions.
CLASS OF LIVESTOCK
FCR AVERAGE
CATTLE
4 : 5 to 5 : 0 : 1
PIG
3 : 5 to 4 : 0 : 1
GOAT
4: 5 to 5 : 0 : 1
RABBIT
3 : 0 to 3 : 5 : 1
CHICKEN
3 : 0 to 3 : 1
Herbage – water grass, sweet potato veins, lettuce, Spanish
needle.
Appropriate Rations for Livestock ~
Feedstuffs provide nutrients for energy, growth and development,
maintenance, production, and reproduction. They can be classified
into the following groups:
Forages – green pasture grasses, legumes, mulberry and neem.
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
Root crops – radish, carrots, and sweet potato.

Concentrates (pellets)

Water
A rabbit’s diet contains cellulose which is not broken down until
membrane in mouth &
food reaches the caecum. Undigested food passes into the small
throat.
intestine into the caecum and appendix where there are cellulose
Fowl Typhoid
digesting bacteria which breaks down and forms droppings which
Coughing & Sneezing,
green smelly droppings.
are egested during the night.
New Castle
Difficulty breathing,
Coprophagy – The habit of rabbits eating small droppings which
Disease
coughing, and sneezing.
enables the animal to derive the greatest amount of nutrition from
the ingested and re-ingested materials.
Caring and Management of Rabbits ~
Like other farm animals, rabbits need a suitable diet to grow,
develop and reproduce. An ideal diet consists of green feed, root
crop, and commercial pellets with clean water.
It is important to clean and sanitize the rabbits’ hutch to prevent
diseases from affecting the animals. Their feeders and drinkers
should be washed to prevent diseases.
Diseases that affect rabbits ~
Disease
Symptoms
Treatment
Coccidiosis
Rabbits look sick with
Add 16%
dull eyes, droppings
Sulfamezathine solution
are loose/watery and
in their drinkers for 5
bloody.
days.
Mammary glands
The teat should be
become swollen, hot,
washed morning and
and red.
evening with warm
Mastitis
diluted antiseptic
solution suitable for
rabbits.
Snuffles
Coughing, sneezing,
Remove animals from
discharge of mucus
drought free areas, small
from nose.
drops of eucalyptus oil
in nostrils.
Myxomatosis Swollen face, red
Vaccination & Isolation
eyes, pus, and swollen
ears.
Parasites
Ear crank, irritated ear
Isolate animals & soften
scabs using cooking oil.
Diseases in Chickens ~
Disease
Symptoms
Treatment
Marek’s
Legs stretched out
Disease
stiffly.
Coccidiosis
Diarrhoea, Blood in
Add Sulphate
faeces, sudden death of
Mezathine to drinking
young chicks.
water and keep the
Vaccination
litter dry.
Fowl Pox
Breathing difficultly,
Vaccinate non-
cheesy yellow
infected birds.
Good Sanitation
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Vaccination