What can i build a shed out of to house rabbits?
You don’t want to use pressure treated lumber. That is treated with chemicals to keep it from rotting, the rabbits will absorb small amounts of the chemical, and it will get into the meat. The new formula is reasonably safe, but there is still a lot of green arsenic treated lumber around- not safe around food animals. Plywood is safe, and naturally rot resistant wood like cedar is fine. But if you put siding on the outside of the plywood, and have a roof over top of it, the wood inside won’t be exposed to the elements and can be regular pine. You could even just use exterior grade plywood with exterior paint. You will need to have a concrete footing, or use treated lumber for the part that touches the ground.