He told me that he bought a fiberglass horse and had it installed in his back yard. I suppose that helped with the anatomy and proportions, but not so much with the articulation.
I don’t think that he would have cared much for mucking stalls.
Some fiberglass horses are better than others. He must have gotten one like this:
It's not so much mucking the stalls as grooming the rascals. Nothing like handling them in detail - currying, combing, brushing, shampooing, braiding manes and tails, picking hooves, etc. to learn how they're put together. Plus watching them move, looking for little lamenesses, helping the farrier, longing them and driving in long reins - it all helps. I'm no artist, but I can draw you a horse, just from 50 years plus of handling them.