With this budget, have you considered a hoop coop?
I thought you were trying to convert a playhouse that you already had, not that you were buying one to convert.
I'm really concerned that when you buy the playhouse you're going to discover that it's a cheap piece of junk that will rapidly...
Welcome to BYC.
I can't comment in re: the snowload issues that have been brought up because I don't have the necessary engineering knowhow to calculate the weight, but here are the usual guidelines about space and ventilation:
For each adult, standard-sized hen you need:
4 square feet in the...