There are 4 million people in the city of Los Angeles and who knows how many dogs. Of its canine residents, the city is sure only of this: About 120,000 are licensed -- as required by law -- and a lot of others are not. "Nobody has ever done a census. It's anyone's guess how many are out there," said Kathy Davis, general manager of L.A.'s Department of Animal Services, who declined to pick a number. "But we certainly don't assume we have all of them licensed." In this time of budget cuts, that spells opportunity for revenue. Dogs don't...