So players create farms and hoard animals, to have easy access to animal products and myst. This is part of the game, and such egoistic behavior is only natural. Apparently, due to current breed/spawn mechanic, wild chickens, cows and sheep are almost non-existent. I was amused to see a player offering 2g to anybody letting him kill 5 cows for a quest in their farm.
Here is an idea, inspired by the way we did it in real world (picture below). After a pair of wild animals has been captured and caged, they turn into a new domesticated kind. This new kind should not count towards the limit of wild animals, and will have slightly different characteristics: faster breeding rates, shorter life, lower output of products and give lower myst when killed. They could be even immobile, for additional realism (*grin*) and/or for reduced server load.
So people will have two options: hunting for wild animals, which is more time-consuming, but has higher return, or setting up a farm with domesticated animals, which is easier, but has lower yields.