I use the 1 gallon for my 11 chicks - 9 weeks old. I do have a backup bowl of water just in case since it is so hot here right now. The temps are in the middle 90's right now and I want to make sure they don't run out of water. I don't think you will have a problem but I would keep a close eye on it in really hot weather. I change mine at least once a day. Also mine leaks some times and I found it almost empty yesterday. I am going to make one to have an extra one when I build an additional run in the next few weeks, I am not impressed with what I have seen at the pet stores.