Hi! I will be the fiirst to admit that I am a horrible gender judge. I thought i had one, maybe two cockerels and at least two pullets,yet one morning I went out to feed and realized literally overnight three of them turned in to future roosters. Now I have a problem. I am unable to get rid of any of them, it would be like giving away my children, so am hoping to build a couple more pens so Ican accomodate them all as adults. Wish me luckOn kitties, the lower opening is oval in a female and round in a male.