You can’t raise purebred chickens of different breeds and let them all run together. It doesn’t bother a chicken at all to live in a coop, especially ones this large. Do a little reading on the subject, something you’ve obviously never come close to doing.
Sounds like you’ve covered every possible scenario for the chick’s comfort and well-being if it’s the only one that’s nutso. If I couldn’t move it out of the house, I’d be looking to cull it.
Good idea with the large limb roost pole! People too often use small, thin roost poles which are not comfortable for the chicken and can even cause bumble foot. Great conversion!