Feeding hay to an exceptionally messy horse?

Spec is by miles the filthiest horse Ive ever met and his eating is no exception. However trying to muck out hay he’s used as a litter box isn’t the only problem, he is very picky with his hay and if it’s slightly wet or on the floor he will not touch it even if he’s starving. It is very painful to be throwing out so much hay that’s barely dirty and I want to find a cleaner way to feed him. Obvious answer is haynets and he does keep his stable clean and eat them no bother but I don’t like haynets as a main source of feeding. Especially given the fact he’s 30 I don’t want him to be hurting his back or neck because he is very aggressive when eating out of one. Also tried a large bucket like on the right but he tips it over and brings his hay to the door of his stable / shelter. Are there any alternatives anyone can suggest that don’t require being in a corner? He’s more likely to keep his hay in whatever it’s in if he can look out into our window. He got the nickname Stalker Spec for a reason!