It's chicken, but it's the part of the chicken no one wants, the part they can get for really cheap. Eyeballs, organs, bone marrow, scrapings off bones, and other gross things. They add a bunch of ammonia, salt, and colorful dye to make it look like real chicken. They have a lot of preservatives in them. They're not good for you.
They are made of chicken, all the bits and pieces that couldn't be made into a profitable product otherwise. They are cooked in oil and have a breaded coating which absorbs the oil, so they aren't really healthy. But they aren't going to hurt you if you eat them as a treat sometimes.
I've also heard that it has silicone in the breading or the skin to give it that crispy taste...not joking at all...that's why I stopped eating them even though they're delicious..but anything that has silicone in it is never good for you.
I HOPE they are made from chicken. I have every reason to believe they are. They taste all right. (I prefer them with BBQ sauce) Since they are a deep fried food, you may want to avoid eating them on a regular basis, especially if you have a family history of heart disease, are overweight, smoke and drink heavily and have a very high stress job. (Heart attack begging to happen.)