I think that would make a great coop! The inside needs to b empty and you need to check for rotten wood, but WOW! I would see if it could be jacked up and set on blocks so that the chickens can walk underneath. It is a good place for the hens to shelter from rain and sun and they keep snakes and rodents from nesting there. Replace the rotted or damaged wood, take the necessary steps to lock out preditors, build a run, and you're ready. That little shed will be cuter than anything else you can build on a shoestring. I still strongly suggest an attached, covered run. It could be the width of the shed (6') and be 10' long. That's perfect for your six girls. I would shoot for a 6x16 run though because of the material sizes, it wouldn't be alot more. The biggest expense will be the hardware cloth or welded wire to put on the run and windows.