Is there a definitive guide on mob spawn limits? I.E. per-player passive, per chunk passive. Do different worlds have different limits? How is a passive mob associated with a player, if per-player limits exist?

I'd like to know what limits are in place before building and investing time in sheep farms.

Thanks,

..Nec

not really.

it seems that in a chunk in the wilderness if you don't use any tricks, that you get by default up to 6 skellies from a natural skelly spawner. In town you could move them around to keep the alive, and drop them on a slap and they can spawn up to about 50 before they start despawning. I went around many towns and found they all use this method. Some for sheep and zombies as well. So design the spawner smartly.

When I place a purchased spawner like cow in the town world, I get about 6 to 8 cows, depending on the angry and friendly mobs around the area, however, the less people online, the less they seem to spawn.

natural spawning also seems to be way way more active when the chunk has been 'tweaked' to  a type (and the surrounding area around it), and when there are more people online. Again the number for natural spawning angry mobs without friendly mobs at all in the same chunk, everything mined and lit up, seems to be around 25 average from a few chunks together, to about 50 at best.

The ratio is low, so the trick is multiple spawners, smart design, and a darkroom, all within the same area. properly lit area and space for friendly mobs in the neighbour hood to spawn.