A pin feather is where a feather that has fallen out grows back. That's typical during molting but also happens if a feather comes out for other reasons. As long as the entire feather and shaft comes out it will grow back in a few weeks. If even a tiny bit of shaft is left in the feather follicle that specific feather will not grow back until the next molt.
When the rooster is on the hen's back he is gripping with his claws. It is not unusual for some feathers to fall out. Usually that's no big deal, but if a bare spot develops it is possible for his claws to cut her. Again, a bloody wound can lead to infection if not cannibalism. This is often caused by an immature cockerel forcing a girl to mate as he is not yet mature enough to win her affections willingly. Some hens have "brittle feathers" where the feathers break easily. Spurs can cut, but most of this type of damage is caused by immature cockerels that don't have decent spurs yet. The claws are the main danger.
This type of damage typically looks a lot worse than it is. I can see some bare skin so there is some risk but I would not put it that high.
My suggestion would be to trim the claws in an abundance of caution. It's probably not necessary but it won't hurt. Just blunt the claws by taking the tip off. I use a Dremel tool with one if those discs you can use to cut metal, like a nail or screw. Some people use pet nail clippers and some use a Dremel tool or electric drill with a grinder head and just grind the point off. If he has a decent spur you can take the tip off of that too so you dull it.
The claw and spur has a quick in it. If you cut into the quick it will bleed. If I nick mine so it bleeds the rooster doesn't even flinch, like he doesn't notice. You might want a little flour or corn starch handy to stop the bleeding but I haven't found that necessary. Maybe that Dremel tool gets so hot it cauterizes the wound. I've learned that if I take off less than 1/4 of the spur or claw I usually miss the quick. The purpose is to take the sharp point off, not remove the claw or spur.
I wrap mine around the wings in a large towel or a sheet to immobilize him. Hold on to the feet with one hand and make the cut with the other. I have no problems doing this by myself.
During mating the rooster grabs the back of the hen's head. This head grab helps him keep his balance and helps him position himself, but the real reason is that the head grab is her signal to raise her tail up out of the way so he can hit the target. There would be no fertile eggs without the head grab. It's not that unusual for an occasional feather to come out but usually there is no visual damage. But it is possible if a rooster (usually an immature cockerel) has bad technique feathers can come out and leave her bald. Or they can grab the comb instead of the back of the head. Especially if the head is bare he can cut her with his beak. A bloody wound can be dangerous because some chickens can become cannibals. I do not see any of this feather loss in your photo.
When the rooster is on the hen's back he is gripping with his claws. It is not unusual for some feathers to fall out. Usually that's no big deal, but if a bare spot develops it is possible for his claws to cut her. Again, a bloody wound can lead to infection if not cannibalism. This is often caused by an immature cockerel forcing a girl to mate as he is not yet mature enough to win her affections willingly. Some hens have "brittle feathers" where the feathers break easily. Spurs can cut, but most of this type of damage is caused by immature cockerels that don't have decent spurs yet. The claws are the main danger.
This type of damage typically looks a lot worse than it is. I can see some bare skin so there is some risk but I would not put it that high.
My suggestion would be to trim the claws in an abundance of caution. It's probably not necessary but it won't hurt. Just blunt the claws by taking the tip off. I use a Dremel tool with one if those discs you can use to cut metal, like a nail or screw. Some people use pet nail clippers and some use a Dremel tool or electric drill with a grinder head and just grind the point off. If he has a decent spur you can take the tip off of that too so you dull it.
The claw and spur has a quick in it. If you cut into the quick it will bleed. If I nick mine so it bleeds the rooster doesn't even flinch, like he doesn't notice. You might want a little flour or corn starch handy to stop the bleeding but I haven't found that necessary. Maybe that Dremel tool gets so hot it cauterizes the wound. I've learned that if I take off less than 1/4 of the spur or claw I usually miss the quick. The purpose is to take the sharp point off, not remove the claw or spur.
I wrap mine around the wings in a large towel or a sheet to immobilize him. Hold on to the feet with one hand and make the cut with the other. I have no problems doing this by myself.
