I'd say the colt almost deffinatly does have ulcers by the sounds of it :/
First off, remove as much starch and sugar from the horses diet as possible (no oats) and feed mainly alfalfa in their buckets. Aflafla is high in calcium so neutralises stomach acid, and it also absorbs some acid. Its good for condition too.
Pre and probiotic suplements help encourage a healthy gut flora balance, and you could go down the treatment road for ulcers. If the horses are insured, you will have to gastroscope them to see if they do have ulcers, then the insurace should pay out for the omeprozole, like $300 for 2 weeks for 500kg horse. Omeprozole is a proton pump inhibitor so the acid secretion is reduced enough for the stomach lining to repair itself.
If you don't want to pay out the $$ ( I didn't) go down the herbal road! I use liquorice root as this has a similar action to omeprozole (obviously less strong) and has really helped my mare. Aloe vera, nettle, marshmallow, pumpkin seeds... many many herbs help with healing and soothing internal ulcrations. Try a few and see what works for your horse!
The above things i suggested are only any good for stomach ulcers. If the horse has hind gut ulcers, these are harder to treat. Apparently oat fibre/flour (bran) can help- but not the oats you would feed as a grain, it has to be the outer bits only. I have also read about a drug with the name something like sucraflates (??) wich forms a kind of band aid over the ulceration to protect it and let it heal. I think this drug might work both in stomach and hind gut ulcers.
Ulcers are *expensive* and often reoccur, its an ongoing battle I'm afraid!
As for the cribbing, cribbing releases the happy hormones called endorphins, and stimulates serotonin secretion too. These chemicals mask pain and are like happy drugs to the horse. The collars are pretty ineffective in my experience and create more stress which means the ulcers will flare up more than ever. To reduce cribbing you need to remove the need (ulcers), reduce the oppertunity, remove the motivation. Eg get ulcers under control, then use collar if you think it works- I electric taped around Alli's field- introduce interesting stuff like licks and toys into the field to reduce the horse thinking 'im bored, I'l go crib'.
My biggest worry with cribbing is their teeth getting messed up to the extent they cant graze properly when they're older, and have to have liquid diets-not good :/
But with propper management, lots of time and patience, and lots of experiments with different feeds and suplements, ulcers are manageable and cribbing preventable.
We lose ourselves in the things we love, we find ourselves there too ~Kristen Martz