It's interesting to read the updates on this thread.
I am down to my last two Cornies. One female, one male.
The male didn't start trying to mate (that I saw) until March/April. They were born beginning/mid August 2017. Cornie King (yep, that's what I call him) wasn't able to mount his girls, even when the girls were laying down. HIs bulk and their bulk was just too much. The King ended up tearing out both of his "toenails" on his little toes. And I suspect, he was the one that injured some of his girls.
The girls had 1" long, horizontal and/or vertical slash marks around their rear ends. It wasn't until I had brought everyone in that I saw the King trying to mount them and realized HE could have caused their injuries.
Outside, the RIR had tried - unsuccessfully - to mount and to mate the girls. He could mount, but couldn't stay on or reach his destination. (Frustrated him so much that he had an anger management problem.)
My one girl laid her first egg a few days ago. Nothing since. I've tried to get a newly broody hen to lay on it.... scared it might be a double yoke. Wondering if it may be fertilized. (My young zebras [boy chickens] successfully mated with her and Baby. And her eggs have been "fertile." That's another story!)
The Cornie girl, Flappie, hasn't laid since. Her sister died a few days ago. When we did the open up and see, we were very surprised to find two egg yolks, but no shell. So we know she was close to laying...
These two cornie cronies will probably move to chicken heaven soon. The girl because she's not laying anything and nothing seems to be working. I can't feel an egg, but she should have laid something else by now. Nada. The boy cuz he can barely stand up on his two feet.
I've learned a lot from my cornies.
For the future....I would put the cornies with a flock as soon as possible or give them their own housing and pasture as soon as possible.
They are amazing foragers and explorers.
I'd put one of my gentle giants with them or a one of my zebra boys with them. The zebra boys are very light weight, very agile, very gentle, very kind, very submissive, and very quick. They don't hurt the girls. It's about release, not dominance.
It's great to know there are possibilities of cornie babies!