What is the likelihood of a horse with daily turnout, low starch/sugar diet, ablib hay/haylage and that was scooped clear a year ago developing gastric ulcers?
There are lots of factors involved and I've read of advice to always give gut support for horses when traveling, showing or anything remotely stressful.
It seems some horses need long term support. Have a google about copra and succeed.
Depends on what else is going on and as others have said other factors, eg,
1. Could the horse be suffering from a low grade injury and be in pain,
2. Is the horse turned out with others,
3. Is adequate shelter provided,
4. Does the horse travel ,
5. Does the horse compete,
6. How often is the horse wormed and with what.....
These are just some of the other factors to consider that may also cause ulcers.
Also gastric ulcers can flare up in as little as 12 hrs so having a clear scoop within a year may be meaningless.
This is a non-professional comment, so please treat as such. One of my current liveries is a fairly recently retired (2011) steeplechaser - high qualiity, won some good races. Came to his current owner for a life of happy hacking. He had suffered badly with ulcers. There's been no sign of them since joining our herd. I can only think that what has helped him are:
Stress-free life
24/7 turnout
very basic feeding ( scoop cool mix, 2 x 600 ml containers conditioning cubes (he was painfully lean when he came), linseed and unmolassed sugar beet twice a day
haylage (substantial amount, though not ad lib)
A vet who rides here told me that 80% of the racehorses in training she has to deal with have/have had gastric ulcers. I think that's an appalling indictment of man's greed and ambition. Our chap is gradually putting on the weight (has taken him over a year) and his owner will always keep him on this regime. So I guess my comment in a nutshel is - keep it simple, keep it stress-free).