Not a bear but I put a whole cow elk in an Igloo 150qt (I think) with frozen gallon jugs. Plenty of room from what I remember. This was bone in. It was one of the ones they have at Costco all the time. I think a couple smaller ones may be better than one large one. That thing gets heavy! Good luck
I quarter up 300 pound pigs into a 75 quart cooler with ease, leg bones in. It’s 8 pieces. 4 legs, 2 backstraps , 2 tenderloins. Bear isn’t much different.