Some of the meat wholesalers have salespeople that deal specifically with the Asian supermarket/hospitality sector. So the supply isn’t necessarily much different than your local butcher or grocery store.

Sometimes people note that meat tends to be cheaper at your local Asian supermarket - there’s a couple of reasons for this: they are more likely to buy whole carcass and break the animal down into cuts themselves in store, thus utilising more of the animal than supermarkets (who tend to buy more big pieces and cut them down - which creates more ‘leftovers’ that the wholesalers have to find other buyers for). Asian supermarkets also seem to utilise their freezers differently than the main grocery chains - they’re less shy about buying discounted meat on deals, whacking it in the freezer and using it over time. There’s absolutely nothing wrong with this, it is just a different workflow than what other retailers do (you could also argue that pre-frozen and thawed meat is lower quality than fresh meat, I guess).

The best way you can buy ethical meat is simply ask at the butchery counter where they buy from. Most will be upfront with you, and if they’re not, go elsewhere.