I just picked up a cheap, used dog house very similar to the one pictured below on Craigslist to make a chicken tractor. (Settled on a chicken tractor because we are renting our place and wanted to be able to take it with us if/when we move in the future.) The roof is made of composite shingles and removable, I might add a hinge to it for easier access and the floor is in 3 sections and is removable too. My plan is to put it up on stilts, reinforce the floor and put in vinyl flooring for ease of cleaning, add a nesting box to the side with exterior access to that, a large hinged door for cleaning on the other side and a little flap door on hinges in front of the existing dog entrance for the hens, which could be closed at night. Roost, poop board, food/water, etc. I'll add more ventilation in it as it's just got the one door. I'd add a little ramp coming down from the doggie entrance to the floor of the run. The run I'll probably try to make 6-7 feet high and maybe 7-8 feet long (excluding the bit under the coop), cover it all in hardware cloth. I have a piece of corrugated metal that's leftover behind our shed that I can use to put over the run. I'll put in a people door on the end or on the side, not sure which yet. I'm planning to hang my waterer/feeder under the coop perhaps. I have no idea how I'll attach wheels in order to move this around. I plan to have 3-4 hens. I have no chickens yet. I am completely new to this whole deal. I've been researching like crazy though and would love to avoid potential problems as I go along in this process. So...all that said, any suggestions? Tips, warnings, etc?