I had a similar thing happen.
4 rhode island reds, all dead overnight in a pile outside the main group in the brooder box.
The group of 24 had a 4x4 brooder box, half heated half not and access to a 13x13 run.
Them getting wet was possible but only from extremely high winds... which I don't think we had.
Eating something in the run was also possible, but I couldn't isolate the cause that way.
In the end I didn't really know what happened, but whatever happened overnight tramutaized the rest of the flock who didn't want to go into the brooder box that next night.
4 rhode island reds, all dead overnight in a pile outside the main group in the brooder box.
The group of 24 had a 4x4 brooder box, half heated half not and access to a 13x13 run.
Them getting wet was possible but only from extremely high winds... which I don't think we had.
Eating something in the run was also possible, but I couldn't isolate the cause that way.
In the end I didn't really know what happened, but whatever happened overnight tramutaized the rest of the flock who didn't want to go into the brooder box that next night.
