I'd just be feeding them sheep coarse mix. Most feed stores do their own. Or sheep nuts, no reason why they shouldn't share those.
The goat wethers will also need a mineral with some copper in it, since sheep foods don't have copper in, as it can be poisonous to sheep, but goats need it. Can you put a lick (red rockie or similar) somewhere the sheep can't get at it? If not, you can give them a squirt down their necks, 5ml of Coppavit every 6-8 weeks.
Not sure I'd want to be getting into something just labelled 'animal feed'. Lions? Koalas? Budgies?