UkPigeonRacing

Mine just have vents on bottom at front and a 2 inch gap all along top and back, I do use limestone flour to help keep dry, I also use a weed wand burner when very, very wet

I have had mine shut in all winter this year. The hens have had access to an aviary and were in it every day what ever the weather was. I used to let them out during the winter and they seemed quite happy flying even when snowing. The only ventilation I have is around the traps and a gap around the top front and back.

Thanks for the answers, very interesting.
It's another way that we have different problems to address.

Forgot to say mine have what some people refer to as late traps on top of each section, one loft they are open and other one they are shut as roofs are different and the rain comes through on one but not other due to it sloping down at front, which stops it

A must in your loft tools, a blow torch for deep cleaning.

I wouldn't be brave enough to use a burner here. Everything is so dry you'd burn the loft down