You may be worried about the wrong things. It is extremely unlikely the two mothers will attack the other's chicks. They don't do that. Their main concern is protecting their own chicks from all comers.
The best time to introduce chicks to the flock is as soon as they can walk. The longer you...
This is old info but still worth a look. Also look up the polish bantam club for members in your area.
https://www.thefeatherbrain.com/blog/polish-bantam-chicken-hatcheries
Never add a single bird to an existing flock. It will be ostracized. As much as possible, you should add like numbers and...
Agree with @Debbie292d.
Your incubator is running at least 1 F low and likely significantly more. You are fortunate to have as many out as you do. The one pipped is likely too tired to complete the process. Whether to assist is a personal choice. If I know my temperature is correct, I rarely...
Unless it is a hen or bird that has brooded the chicks, the others will take time accepting chicks into the fllock. Once accepted as flock mates, it is rare for a bird to become ostracized, but t happens.
The pecking usually happens just to let them know who's boss. At least till they grow up...
I think it is a good choice. I wouldn't worry about off gassing. The powder coat is baked on and cured at over 300F and probably for at least a half hour, maybe several hours. The temperature it will operate at is much lower.
I have to agree with the two previous posters. I'm 95% sure your problem is a lack of ventilation and a buildup of humidity. It happens fast. The moment you close the coop door.
I recommend a hygrometer, preferably one that tracks or records data.
I once had doubts about ventilation in one of...
Without understanding your explanation completely, I can say two things. If in doubt, you likely don't have enough ventilation. And secondly, if you are building your roof around a tree and it isn't completely enclosed, you likely will have a predator problem.
Chickens have tiny respiratory...
I'm not a genetics expert and I don't know how this pertains to your situation. But years ago, I had an ongoing issue with white feathers showing up on black hens after their first molt. Not roosters but only hens. I had a discussion with a poultry genetic expert residing in Europe. She...