Thank you! While I was waiting for responses I went back out to the coop and it was better-- the day has warmed up slightly and the nighttime damp is drying off a little. I did realize that there is a draft coming in from the pop door and I'm on my way back out there to block the draft from that end of the brooder with thick towels and rugs. Unfortunately I have positioned the MHP cave opening as facing the pop door (accidental) so that means the draft can go in there :( But I'm reluctant to change it around because the chicks are confused enough. I wound up keeping them in the house 3 nights and used a smaller heating pad I had on hand to create an ad-hoc MHP for temporaries. The one for the coop wouldn't fit in the brooder cage indoors.
We have housecats so I had to ensure they were tight and safe. I took the opportunity to inform my cats that these are "MY chickens" and they mostly stopped lurking. Also, to answer another recent query, our cats, even the fiercest hunters, are terrified of the adult chickens and give them a wide berth. I am working on solutions about the chicks and the cats outdoors. Our cats are not feral and we feed them quite well, so they don't hunt from necessity. We have 2 cats who hunt mice and rats, which we approve of, but they also catch lizards which we do not. I have not found any feather evidence that they are catching any birds. But, the chicks are vulnerable. So I'm thinking about it. I do expect that the chicks will stick to the adults like glue and since the cats don't go near the adults... but I'm not sure. Will observe and adjust according to observed behaviors.
One other thing-- while in the house I had the heat lamp (infrared black ceramic bulb) on them in addition to the MHP. This was mainly because I had trouble with the incubator and I couldn't leave the chicks in there as they were hatching. Long story. Plus I had 2 chicks with problems that I assisted according to the cautious and careful instrux via BYC. Anyway, I had 2 delicate chicks and a bunch of chicks that were wet when I put them in MHP so I used the heat lamp to ensure ultimate warmth and comfort. This confused the chicks when I put them outside in the coop because they were used to that heat coming down on top of MHP. So, if at all possible, really REALLY recommend not using heat lamps during the first few days if going to move them outdoors.
Just a report on my hatch-- started with 22 eggs from our Easter Egger hens with our blue Americauna purebred rooster. Wow beautiful color he threw, can't wait to see them mature! 4 eggs were clears, so out of 18 fertile eggs, 11 hatched and one passed away (I kept her in my bra so she had me the whole time, it was clear she had imprinted and I loved her too). So I have 10 beautiful chicks. Will try to get pics up... I'm behind on work (I work at home) and desperately need to get to it!