I was inspired to make a similar design from your plans when I ran into the problem that I have nowhere to get free plywood. It's pretty rare around here to find plywood for free...
I changed my design after that. I could deconstruct old shelving units that people give away for free around here. Using the space inside the pallets for insulation (by packing in newspapers) I could use particle board backs inside the coop and the sturdier shelves, sides tops and bottoms on the outside. Then just paint the whole thing with weatherproofing paint. The coop I have planned isn't as big as yours but it does look pretty nice. (On paper at least!)
I changed my design after that. I could deconstruct old shelving units that people give away for free around here. Using the space inside the pallets for insulation (by packing in newspapers) I could use particle board backs inside the coop and the sturdier shelves, sides tops and bottoms on the outside. Then just paint the whole thing with weatherproofing paint. The coop I have planned isn't as big as yours but it does look pretty nice. (On paper at least!)