Digestive System, Part 3: Avian
The avian digestive system is way different from the systems we talked about in the previous two posts, it's different than monogastric systems as well. As some of you may know, birds do not have a stomach, or teeth for that matter. This means that they must have some other way of breaking down food for it to be absorbed into their body.
This system includes three different parts before the small intestine. These parts are the crop, proventriculus and gizzard (ventriculus.) These parts help aid in breaking down food particles by mechanical and chemical means.
Let's start at the crop. After food is picked up and swallowed it enters the crop. The crop is basically a pocket that holds feed and water. Similar to the stomach in monogastics, the crop will send "hungry" or "full" signals to the brain.
From the crop, feed then enters the proventriculus. This muscle is considered the stomach in birds. It releases acids and other chemicals to aid in breaking down the feed. Now, remember, the feed is still whole at this point in time. It stills needs to be broken apart so the bird can better absorb the nutrients into their body.
From the proventriculus, feed enters the ventriculus (better known as the gizzard.) This is the muscle that does all the hard work. This is where adding "grit" to a chicken's diet becomes important. With help from the gizzard walls, grit grinds and mixes the feed with gastric juices. Free range chickens will typically pick up small rocks, but chickens kept in confinement will more than likely need a supplemental grit. Luckily, the Farm Store sells this in five or 50 pound bags. The five pound bag costs $3.75 and the 50 pound bag costs $12.00.
Hopefully you have learned something about the digestive system of birds, it not, that's alright to. Thanks for reading!
To read more about avian digestion, click here.As always and until next time,