I just ran some numbers and I have a December hatch set. I found my only bantam dead in the yard today. This is also the day she laid her first egg. I don't know if any of my standard size roosters mated her, but I am going to try and hatch her only egg anyway. It id due Dec 1st - 3rd. (I don't know if she is an 18 day or 21 day bantam. (TSC bantam bin, laid a white egg.)) I added a couple standard size eggs into the hatch as well, for company. This makes a third chicken egg hatch for the season.