Some good questions...and answers. The brooder is outdoors. (I posted a picture of it under the coop section last night, but don't know how to put the same pic here without having to upload it again and use up my space for pics)
As I live on Whidbey Island in the great (soggy) Pacific NW, the temp has been hovering around 40 during the day and around 35 at night, so quite chilly.
I have two clear heat bulbs and one red in the brooder and the floor is 1/2 inch hardware cloth, but with sections of plywood under the heat lamps to prevent injury if they huddle a bit under there.
They are on regular chick starter with no treats, just water. I have a limb for a roost that has all sorts of interesting little bits of moss growing on it and long strips of wide bark peeling off in sections. Sounds like it ought to keep them busy at least for a while.
The main chicks really being pecked up are the darker colored ones, right on their backs. I think its the two austrlorps.
Hope that helps with the questions. I'll try removing one of the clear heat lamps tonight and see if that makes a difference.
Thanks!