Re-introducing rooster to flock

[Farmer_Jo]

I pulled my two roosters out of my flock because 1 was balding and being pecked by the hens. I pulled the other one just so he would not dominate and I would have a fight to the death when I re-introduce my fully feathered senior. The junior rooster managed to make it back with the flock. I was going to separate him again, but with the cold coming I do not have a good way to keep him warm by himself. Any suggestions as to how to re-introduce my senior to the flock when he has regrown his feathers? TYIA