Good news--ish. We only lost three last night.

I'm calling Murray McMurray in a minute.
Its only 100° in the area directly under the lamps--about a 10" radius. They have about a 4'x4 area to move around in, and it's freezing outside, so no one is sitting at 100°. Most were around 90° or so. I just lowered the average temp away from the lamps to 78°, but they immediately went under the lamps or huddled up, so most are still choosing the 90° zone. That's about the same as any of my other meat flocks have done at this age.
The brooder house is an 8x8 concrete building. I have it partitioned with cardboard and cinder blocks so that I can open larger areas as the chicks grow. The floor is concrete, but covered with fresh pine bedding. (I generally use the deep litter method, but I rearranged some things, and it had been a while since any other birds had been in there, so it was easier to just put down fresh bedding.) The feed is stored in a partitioned area in metal cans. Ventilation is at the top near the roof. The door can also be vented in warm weather, but it's sealed now due to the cold.
There is no odor of pine, ammonia, or mold. I also don't see any mold. That would have to be some fast growing mold, too, considering I put my eyes on every square inch of that place, including bottom of feed cans before those chicks went in there. It smells sweet in there, like it should. My whole family has pretty bad allergies, so I'm super cautious about dusty bedding, mold, ammonia, etc.
I'm hoping we're past the worst of it. Everyone is still having labored breathing, but they seem to be stabilizing. They were moving around more and eating better. I would like for them to drink more, though. I tried dipping a few beaks in the water, but I couldn't make them drink.
I know it might be just because they're focusing on breathing, but does anyone think there may be different reason as to why they won't drink much??