You're welcome! Sounds like you have it all sorted. I know what you mean about hawk protection - they are stunning creatures, but i just wish they would not eat my chickens! I let mine free range (in a similar size property to yours) and consider the occasional loss as part of the bigger picture...
Sounds like a good plan - I hope that some BYCers with more imagination will chip in, but from a practical, rather than aesthetic point of view here's a couple of things I would consider.
1. Are there other windows in the shed / playhouse that can be opened for ventilation? - opening the...