I lost 2 pullets and a hen last week, and am left with 4 RSL hens and a (slightly traumatized) silkie cockerel. I have 4 Black Australorp chicks that are being raised inside still, at 5 or so weeks old. They aren't fully feathered yet. I got them from a lady who gets chicks from hatcheries and raises them to the age that people want. She has some Buff Orpingtons that are 8 weeks old, and I was going to get 3 pullets from her today. I was initially just going to segregate the slightly older BOs in the coop, and when the BAs are ready to go out, integrate them with the BOs and after a while let the whole flock mingle, just free range together at first and then try to integrate everyone in the next couple of months. My RSLs are bossy, but not terribly territorial. I just didn't want to replenish the flock starting with day old chicks from somewhere. So:
1) should I quarantine the 8 week olds for a full 30 days, or just segregate them in the coop? The BAs I got from this lady are healthy, and other individuals I know have bought chicks from her with no complaint. Her holding shed is segregated from her personal flock, but the chicks are exposed to whatever pathogens she brings in on her boots, at the very least.
2) should I wait to put the BAs in, or just go for it? They aren't fully feathered, as I said - and I think they'll be too cold out there yet. Would the 8 week olds be too big for the 5 week olds & cause harm? I'm in upstate NY, and it's still dipping into the 20s at night. The coldest the BAs have experienced is 60 or so in the house (if the fire in the wood stove dies overnight). I do have a red heat lamp that I can use if need be, in the coop. I don't use it often, but - if it got really cold, I could keep the coop warmish.
3) I always appreciate advice, so thanks in advance. I've done ok for a year or so, minus predator attacks. I just tend to err on the side of caution, but I don't want to make things needlessly hard on myself.