In California, that shot is illegal unless you take the shot from more than 130 yards away.
Never shot a deer in a barn, but have seen mulies use old cabins and outbuildings for shade before. Especially out in the flat-lands of eastern CO and KS. Buddy of mine took a picture of a monster buck in an old shed in Eagle County several years ago. Would love to have that kind of cover to sneak up on one!
He missed the first shot.
Guess I would need to read the CA regs. Not sure why it would be illegal to shoot an animal in an abandoned outbuilding. Really makes no sense that you would have to back up to more than 130 yards away to shoot a critter in an old abandoned outbuilding! Heck, I would have a tough time hitting the barn from that distance with my bow!!
Once when hunting plains muleys I spotted a giant buck laying in a cattle loafing shed. It was all open in front of him so I snuck along the back and at one point was only 2 feet away from him through a corrugated metal panel. I know this because there was a hole right there and I could have poked him with a stick. But the hole was too small for my Muzzy broadhead (I know this because I tried to fit it through the hole)
I tried to slip around the back side toward his rear with my longbow drawn but he caught my movement and bolted.
No, but we Hunted Doves outside of Vona Colorado for years. It wasn't uncommon to jump a buck out of an old shed, farm house or barn. Usually big ones too.
I knew a couple guys where I used to hunt and they were on the trail of a wounded buck. I tagged along and the blood trail brought them to the door way of a feed lot feed quonsette. Sure enough that buck was way in the back up on that feed chin down. I don't think it was his first time in there.