I pulled them out individually by attacking, and killed them in place- until about halfway through, when aggro'ing one aggro'ed 4 of them for some reason. I ran away to the entrance to reset, and got the below result when I killed them.
(Note that my survival is 102)

For those not used to Ender, the numbers above the corpses are the quality for the corpse.
See that their quality goes down as we get farther from the spawn room? This gradient extends out to the right of the room as well, with two 3 more corpses that drop off from left to right, all the way down to 60.
It looks to me like the animals get assigned a quality based on their location when they die, not where they were when they spawned. Is that the case? The only thing that makes me doubt that is the lone 93. I may have moved that in some way. I don't remember. It just seems unlikely to get this gradient so clearly, when they were all mixing around in the spawn room.