I'm hoping it's nothing, BUT! So I got these 6 horny hens as I like to call'em. Beautinful Buff's, there right at 18 weeks and for mabey a month now I've noticed on about 3 of them, their tail feathers are black? Just the tips, not black black but not buff at all. It started out spotty, again, just at the tip(the last 2-3 inches of the tail feather). If I didn't know what I was looking at I would say it resembled mold as some mold starts out spotty, but I'm thinking it can't be mold. Is it normal? They free range and seem happy as can be. I've been a chicken owner for all of 18 weeks so I'm just trying not to neglect them. If anyone has any input I would grately appreciate it. Have fun out there!