aha, yes i had read about that...
.so i just put in a couple of screws at the very bottom under the sliding door, into the sill. So the door never actually rests totally on the lower sill lip. (gap of 2-5 mm is sufficient) Even with all the snow, melts and hard frosts it did not jam. The other thing you could do is make a sort of covered porch area so rain and snow doesnt land on the runner - guides and sill of the sliding door. Also I made the door out of a plastic board thing so the snow etc is less likely to stick on it!
HTH Emma
I love it, this is all part of being self sufficient...the problem solving and the working with what you have in a creative way
. Personally I decided that I would rather have the hens trapped inside for a day than all slaughtered by the foxes. I do always have fresh food and water in the hoose so they are not suffering. Also if the weather is really that bad the hens would probably want to stay inside anyway. HTH