hello,
I have some BA pullets that are 13wks old. I have 11 total, there is 5 of these pullets that will not stop pulling out tail feathers then they eat the feathers. I thought they may be lacking something, so I added shells and protein. The other six birds have feathers. These birds are hatchery birds, but i do not understand this action. I have other breeds and have never had this. They have plenty of room and food, they seem to just do it for fun. I have no idea how to stop this if i can get some advice that would be nice. They just started this the last couple weeks. i want to breed some of them with a BA rooster i have, and some to a black/lav orpington split.

Have you seen them pull out the feathers? BAs go through a mini molt at this time and they will eat the feathers sometimes when they fall out.
If you have seen them pull out the feathers, you can buy plastic clips that will stop them from pulling out feathers. They can still eat ok, just can't pull out the feathers.
If they are plucking out their own feathers, it could be over preening which is often caused by mites or lice.
I hope this helps!