I agree 4 inch side flat for roosting on... less frozen toes, as the feathers cover the whole foot then. I have some that just perfer a platform so we will see if they will roost after I make the changes...jackhorn01--for large fowl lay the 2x4 on the 4 side flat, in the winter they can cover the feet entirely to keep warm, and the heavier breeds need the extra inches to help prevent breast sores. One of my black orpingtons came with one that been just terrible to get it healed, 4 months later she still has it--it's getting smaller.