The portable coop is 12ft by 10 ft
Wow, that's some portable coop!
I have no clue other than that many birds working too hard on each other to establish a pecking order.
Does it seem to you the deaths are solely from pecking?
If you could take some pictures of the birds (the whole group and...
Welcome to BYC. Hope you find a lot of answers here.
How long/wide is the movable coop?
40 birds together in a too-small coop can cause death and injury due to crowding.