Coop fans

[khind]

: ( Oh, no...

 

[ChickenCanoe]

I use a big cheap box fan like @aart has sitting on the windowsill of my coop with the least ventilation. I just bought a new one. The old one lasted 4 years running year round. It perfectly fits the window opening.
Except in the most extreme conditions, you can't get too much fresh air into a coop.

 

[City Farmer Jim]

The 2 fans I'm picturing are 7 inches but that's just the blades. Total outside dimension is 11.5 ish they came with extra mounting brackets that adds another inch. My roost bars are at exterior vent height so the fans draw in ambient air across them and out of the coop. I tried blowing air out of the coop but the girls didn't like that at all.

 

[ChickenCanoe]

When using fans in poultry housing, you have two types of air flow: positive pressure and negative pressure.
Basically, blowing air in is positive pressure, blowing air out is negative pressure which brings fresh air into thee coop from openings and cracks.