Look at 1-duckling's photo...that's enough for 20 eggs. I haven't done this yet and don't think I will because don't have enought backyard space for that many, lol. But I don't know how that would go, I know with my 12 egg carton I had only 6 banty eggs in there and with the humidity pad that drops down a little towards the egg carton. I'll try to get a closer pic of it where you can see my setup.