I never heard that about snakes and mothballs, learned something new. Problem is, it's very difficult to find the old type of mothballs any more, they quit using the napthelene years ago. As for the chickens getting them, I'd surely be careful there, it could kill them. I'd put the mothballs in a one pound coffee can with small holes punched around the sides so the smell gets out, but little beaks can't get in. Then tape on the lid with Gorilla tape (way better than duct tape!!) so the lid doesn't accidently come off. You didn't say how small the chicks were, but I am assuming very little babies? If so, it may have been a snake, but would have to be a rather large snake. They take a long time to digest stuff, so swallowing 4 chicks would be a feat...I would think?