There's a horse at our barn who is very skinny, has a dull coat, and his trainer (they're fairly new at our barn) mentioned that he doesn't shed out like their other horses and maintains a relatively long coat all year. She claims he's skinny because of his age, he's 21, but that just doesn't sound right with the coat. My trainer has a client horse with Cushing's that's been diagnosed and properly treated for a long time and he's pretty normal, and that's why I thought of it.
The question is, is there a way I can suggest testing for Cushing's to this trainer without being confrontational? Or should I just stay quiet? She's a very nice lady, but a bit of a BY trainer considering the methods I've seen her use in training and instructing. I don't want to insinuate that I'm more knowledgeable/have more experience and come off rude, but I hate to see a horse in that condition. Any suggestions are appreciated!
ETA: In my opinion, age is not an excuse for an unhealthfully skinny horse. It may make things harder, but in my and my last two trainers' experiences there is usually an underlying cause that need to be addressed.