My warmblood was a cribber when I got him. I refused to put a collar on him, I think those things are horrible because the horse is cribbing FOR A REASON and it's my job as an owner to figure out why and fix it. I see horses all the time who have those collars cranked down and still crib.
I did more research on cribbing and found that horses a lot of times will crib because of digestive upset due to ulcers/other pain/stress and excess acid in the stomach which could be a result of not getting enough forage through the day. Being turned out 24/7 is best and the horse should have free-choice hay all day long. The amount of grain the horse gets should be as little as possible and the hay shouldn't be high in sugar. Alfalfa hay or an alfalfa mix hay acts as a natural buffer on the stomach, so feeding a couple flakes of that a day can really help.
When I got my warmblood home unfortunately I couldn't keep him at my own house, I boarded him over at a friends private barn. He was not getting enough to eat and lost a lot of weight quickly....he was very overweight anyway but he shouldn't have lost that much that quickly. I wasn't too pleased with the situation so I decided to try a product called SettleEx. It's a powder you put in the grain and it helps reduce excess acid in the stomach. It's distributed by FeedMark, www.feedmark.com
That really helped him out a lot. When I was finally able to get him home to my own house he was out 24/7 and had free choice hay all day long. I then decided to treat him for ulcers b/c he was still cribbing some and after treatment he all but stopped cribbing. When he did crib I noticed that it was almost like he thought he had to, like it was a pattern. So I would interrupt that pattern and back him away from the wall and that was the end of it. He only had the opportunity to crib when I fed so I was there each time he tried.
We recently moved to a new place and there is this one section of fence where he could crib if he wanted to but there is not one tooth mark on that fence. He hasn't even tried to crib.
I disagree with the idea that other horses will "pick up the behavior." IMO that is completely wrong. It's just a myth.