As someone living in vacaville and just in my begining research for chicken laws, I looked up the animal code on the city website and found a few of these interesting in relation to the animal control person who came around.
As far as possesion of an animal in less than 1 acre:
6.04.040 Animals Prohibited on less than one-acre lots.
Except as otherwise provided in this chapter, no person shall keep, corral or harbor any cow, horse, sheep, goat, hog or cloven hooved animal in the city on any single parcel of property less than one acre in size. (Ord. 1462 §3, 1992: Ord. 1286 §1(6.4), 1986).