Anatomy, while not something often thought of, is a major part of a chicken. Many people know where their own heart, lungs, stomach, and other body organs are located, but few know where a chicken's body organs are. Knowing the location of different parts of a chicken can help you identify illnesses and potential problems. Of course, a hen's body will be slightly different than a rooster's. It's a bit harder to get pictures of the inside of a chicken, so please excuse my lack of pictures. Let's start at the top:
Chickens eat food and shortly later it comes back out in a less appetizing form. The food first enters the beak and goes down the esophagus (throat) and into the crop. The esophagus doesn't have any muscles like our throat does, so the chicken relies on gravity and its flexible head for the food to go down.
Simply put, the crop is a storage area for the food and water until later processed. The crop is easily identifiable as it is located at the top of the breast and appears to be a large lump in the bird's front when the bird has gotten to eat enough. Typically, the crop is large at night after a day of eating for the chicken.
Here, food from the crop is moved and digestive enzymes are added before going to..
The gizzard is where you'll find the grit or pebbles your bird has swallowed have gone. These pebbles or grit along with the muscles in the gizzard help to grind up the food so it can be absorbed.
From the gizzard, the food and nutrients are absorbed through the intestinal walls of the intestines where the nutrients will be distributed through the body accordingly.
Whatever the intestines left behind (waste) is passed out the opening at the rear of the chicken, the cloaca. The cloaca serves two purposes as it is also the same place an egg comes out of in a hen. Don't be grossed out, though, a hen's body works things out so that the egg does not pass through any other place waste does other than the brief time through the cloaca.
Located beneath and between the gizzard and proventriculus, the heart has the same purpose on a chicken as it does for any other animal. It pumps blood through the chicken's body to deliver nutrients.
For chickens, their lungs are actually located under their back between the neck and tail. If you hold a chicken upside-down, it can limit their air intake, so it's best not to do this for too long.
To be finished soon!