When I first rescued Relevante he had a decent mane...over the winter and this summer it has progressively thinned/shortened....I’ve tried MSM, bathed, done braids to help prevent breakage and rubbed in other products into the roots designed to stimulate growth (I have caught him trying to stick his head through the fence to reach grass on the other side which is out of his reach and at first thought that this was possibly the reason (and prior to being bathed also noticed him once rubbing his crest against the edge of his open doorway to the paddock  but now I’m thinking it’s something else/maybe something he is lacking because it looks like the whole mane is being affected (my vet thought that might be the case as well but admitted he had no suggestions). Could this be related to Cushings? I'm concerned in the event this is a symptom of something else that needs addressing.