Quote: Using lower venting did not work for me. My first coop was a smaller raised coop with venting in the top eaves. That first year I had some small issues with frost bite, but not every bird was having a problem. I left every vent open and even cut more holes in attempt to create more air movement. I believe that the space of the coop was just too small for all the breathing and pooping going on and the air was just not moving fast enough to be whisked away from the birds and combs.
So I decided to try putting in a lower vent in hopes to help suck the air from near the floor up and out the roof. I made sure this venting was not blowing on the birds. All this did was make it 10 times worse. I was getting much more frost bite issues with every bird now.
We eventually built a another much larger coop with an angled roof. Venting at the eaves of the roof at both sides of the lower and upper end of the eaves. This solved ALL the frost bite problems. The air is drawn into the lower side of one eave and is sucked out the upper eave on the other side. The birds roost low to the floor in relatively quiet air spaces and the moisture from the pooping and breathing is lifted up into this positive air movement. I have not had a single problem with frost bite since, even in the most brutal of cold.
I think it all depends on the design of your coop. If you have a coop with an angled roof from one side to the other, this helps with creating a positive movement of air. If your roof is flat or peak shaped, lower venting might help to better create this needed positive air movement.