Consider a wholesaler, or local butcher. If you have connections w/ someone in the food/restaurant business, see if you can go to The Restaurant Depot (here’s a search of Chicken Wings) if they have membership which should be free for food businesses/restaurants or qualified non profits, or buy a day/guest pass and go yourself.

PS: You can also order online from the Restaurant Depot via Instacart depending on where you are. Same concept if you were to order from Costco using Instacart (even w/o their membership): yes it’s possible, and yes, things will be pricier.