hock injections are very common in jumping horses- with a busy show career (showing 2-3 weeks a month) it is normal for them to need their hocks done at 8. most jumping horses that show have their hocks done by 10 if not before. hock injections doesn't equal a problem its just maintenance.
I wouldn't say hock injections are "very common" for 8 year olds. You would only inject a horse if they were starting to show signs of arthritis and for an 8 year old to be showing signs of that highlights everything that is wrong with the horse world. In my experience, which I'll admit is not that extensive, it's common for more seasoned show horses to need injections as they're coming to the end of their show career but their owners still want a couple years left of jumping out of them. For an 8 year old to need hock injections is not exactly normal. ??
How many lesson horses are at your barn? (Estimate) what are some of their names?(you don't have to list them all, but lost some we have never heard of before)
Not that many, around 5? Lily, Ben, Endy, Tuffy, Angel. I'm not sure, there might be more than that.