I shouldn't say bad genetics, just he's not a hardy horse. Say compared to my Morgan. My Morgan was 17 and an easy keeper. His feet, main, coat, everything about him was wonderful a big strong powerful horse. Now my daughter's cremello (which is Perfect for her age, size, and ability) is super sensitive to everything. I have to water down his pasture because the dust irritates his eyes, watered down his hay (have since moved him to cubed alfalfa and water it down too, has a finer build of course, very slender to skinny, hazel eyes, (yes hazel not blue: has issues with depth perception: he's still in a tune up, but has never been really sure footed). Rode him moving cows a couple of times and the breast collar wore his hair away in two spots on his chest: just a normal leather breast collar and moderate hills: not really many steep up and down hill climbs at all. I've never had that happen with any other horse before. When he rides in the trailer, even to short trips to the ridding arena he rubs his tail against the door and makes a bald spot on his tail so I have to wrap it before I haul him. People would say he had worms because of the rub (but he's on a regular de-worming schedule. So I guess I shouldn't say bad genes just not nearly as hardy as other horses I been around.
The hardest thing about learning to ride is the ground!