We had some pecking and we ordered these to see if they would help. We've had them on for a couple weeks and the pecking has completely stopped! It was a little tricky to get them on but after we did a couple, it got easier.

The Peepers are great, the only problem is that I ordered too many by mistake. I ended up with 4 times more than I needed. I only have 8 chickens.
I have 1pkg. unopened and completely sealed that I had hoped to return but can't.

We're new to chicken keeping this year, all was well until winter cold hit in, possibly combined with a molt and some food issues and one day seemingly out of the blue our flock of 10 started to feather pick and vent pick each other bloody. We separated the injured ones and tried things like stop pick spray, pine tar, covering the red/flesh with activated charcoal, adding in extra treats and a more stimulating run. Nothing seemed to be working, we kept getting more injuries. Someone online suggested trying the pinless peepers, as the only thing that worked for them. Our local livestock stores didn't carry any and I don't use amazon, so I was glad to find this website. Just 1 province away, with a good price for a bundle, including the pliers.
They even upgraded to a faster shipping for me, since we were in such turmoil and at our wits end!
Installation was a little bit tricky, definitely needed two people, and some patience to get the little nibs slid into the nostrils, but underneath the soft fleshy covering so that it's not hurting the chicken. Softening the peepers in hot water helped a lot. Once we got them in the correct position, they stayed put. There is a bit of comb squishing, but that's a small price to pay.
So far, they're working way better than anything else we tried! Aggression is definitely down. There is still some feather picking but much less, and it could be self inflicted/grooming/molting. All 10 have been back in the run for a few weeks and there are no horribly bloody vents or dead chickens, so that is a big win! Knock on wood that it keeps working. We haven't tried removing any yet, to see if the aggression issue is fixed, but we will soon. They're supposed to be removed every few weeks to make sure the beak health is okay, but all looks good on visual inspections.
Customer service was excellent, I will be returning when I need more peepers or any other goods.