No damage and no sprouts to indicate feathers coming in... he may just never develop the typical tail. There are a lot of flaws that can present themselves, from funny shaped combs to weird feather patterns to all manner of other things.
Raising birds can get really disappointing if you were expecting a certain look and they mature differently. Like buying Rhode Island Reds with the image of the nice quality ones in mind, but getting Production Reds instead that don't even have shiny feathering. Jersey Giants that never get big. French Marans without leg feathering, Bantam Cochins that aren't shaped like a basketball, Silkies with minimal fluff, Seramas that look like Old English. A rose comb where there should be a single comb or vice versa. Brown eggs out of something that should have a different egg color. I have a white egg coming from a brown layer, for example.
These inconsistencies are to be expected from hatchery type birds or general purpose breeding. For example, if someone hatching eggs hatches from every hen out of a free range flock with several roosters, quality will be spread across the board depending on who mated with who and which traits from each parent were expressed. If someone sits down and evaluates each bird, and sets up only the best looking ones into a breeding pen, then the results should be more consistent. But even with selective breeding, only about 1 in 3 will turn out as hoped.
He could also have had a close encounter with a predator or some other such thing that wasn't seen. I had a hen pull her own tail out by wiggling herself under a fence. I found her in the neighbor's yard and found the feathers stuck in the fence where she went through. It does take several weeks for a tail to regrow if that's the case. If he never did have the tail though, he just may not get one. If you were going to breed him, I'd see about finding a replacement to reduce the spread of that trait.
Another time I had a hen that was just not shaped right. The bump that the tail grows from was skewed, and so the tail drooped sharply to one side. I had to keep it trimmed to keep it from getting poo built up on it.