I am about to purchase wood for my run and wanted to know if I could use PT wood without ill effects. There will be no feed or water in the run around the wood, I will keep it in the coop.
PT wood is necessary only when close to or in contact with soil.
Ground-contact rated lumber has .40 pounds of preservative per cubic foot. Above-ground rated lumber has .25 pounds.
You can use above ground rated treated lumber in contact with or in the soil but it wont last as long.
WEll i only build a doghouse so far. I used treated 2x4s for the ground contact and after two years outside in our kansas weather it holds up just fine.
We used pressure treated, but put these sleeves over them so the chickens wouldn't peck at the wood. I think they came from Home Depot, so they are easy to find.
You can see a photo of them on my page (you have to scroll down a bit to see the run). The sleeves are white.
Happy building!