There is a substance in turkey called "tryptophan". Not sure if that is spelled correctly, but that is the name.
Anyhow, they say that it is what is responsible for making people tired after they eat turkey. Chicken also has this in it, but not as much as turkey. I have just recently read an article that names a bunch of other things that have this in them as well. Unfortunately, I cannot remember all of the things it said, but I have the article at home somewhere. It was talking about things that you could eat when you are ready to go to sleep that will help you to sleep better because they have "tryptophan" in them. I believe bananas was on the list, but can't remember what else.
It is kind of an interesting subject. Now you have made me to wonder about those other things, so I will probably try to find that article when I go home. If you want me to tell you what else it said, then you can ask me and I will try and remember to tell you later.