I figured it was humidity so I put a few more vents in but also I got rid of 8 large roo's at that same time. I've had this set up for 3 yrs but this yr I had 8 more birds inside. Like I said, it hasn't happened again after adding the extra vents. My birds don't seem to mind the cold at all, or rain. But let it snow and they don't come out. Must be southern birds.
Can your birds get to the fleece and do they peck at it?
TOB I'm so sorry about your dog. It's so hard to lose a family member.
Vents should be strategically placed. Directly across from one another. So the cross breeze will "draw off" the warm moist air. I haven't noticed the fleece being picked at. I wouldn't use a red pattern though. The coop in the picture has fleece on one side all year long. In the summer it gets too hot.
This coop is in the shade and the hole you see they may have picked but then it is green, like grass I guess. They haven't made it bigger though so I guess they're leaving it alone. The fleece covers hardware cloth on the front of the coop. I have feed bags covering the back. It sits into the woods a bit and is shaded in the summer.