I'm in the same boat... but no chickens yet. Though I have this fabulous dog run complete with a hole already cut into the side of the shed. I was thinking on ways to get a roof on there, part solid for weather, the other part wire.
Was thinking about a way to do a wood frame that "sits" on top, secured with U bolts. Slightly higher on the one side for rain runoff. But the gutter on the shed is in the way on that side. Not sure how to work that.
I'm going to leave it to husband to figure out.