outershell isporoussothatair can passthroughit to thepapermembrane.
The outershell also provides protectionfor all theinternalpartsof the egg.
The variouspartsof thefamiliarchicken egg are secreted in the body of
the hen and pouredaroundthe yolk as it is passingthrougha tube on its way
to theoutsideofthehen'sbody;the shell doesnotbecomeharduntil the egg
reaches the air after leaving the body of themotherhen.
STUDYING THE DIGESTIVE ORGANS OF THE CHICKEN
Materials:Ask thebutcherto show you the digestiveorgansof a chicken.
The liver and thegizzardare easy toobtainbecause they areincludedamong
the ediblepartsof the chickensyourmotherbuys.
You will observe:The tubethroughwhich thechicken'sfoodpasses before
it is digested issimilarto the humangullet. The liver, which we eat when
cooked,is abrownish-redshadeand consists of two sections. Unlikethe soft
liver, the gizzard is verytough and looks like a thick bag. The intestine
resembles a sleek coiled tube.
The chicken eats mostly corn and othergrains andsome small gravel
stones. After being takeninto the mouth,the chicken'sfood passes down
the gullet into thetopof thestomach. Itthen moves on into thetoughorgan
called the gizzard or crop. Thereare, in the gizzard, stones or pebbles that
grind up the food. Oddly, these stones serve the function of teeth. The
chicken'sfood is chewedafterit is swallowed, for like otherbirds, chickens
have no true teeth.
Once it has beengroundinto a finepowderin the gizzard, thechicken's
foodpasses on to the intestine. The liverandotherglands supply digestive
juices to the smallintestinewhere the food is digested.
If you have a petparakeetorcanary,it is wise to includein its diet tiny
pebbles thatit can takeinto its gizzard to aid digestion.