Do I need a license to foster dogs?

There is a rule in the town I live in where you can not have more than 3 animals in town. Well I take in alot of dogs to help find homes and such. Well I was wondering if I need some sort of license to protect myself from the animal control coming to take my dogs? A rescue license maybe? And just so you know I am NOT an animal hoarder looking for a way to keep loads of dogs legally. I only keep 5 dogs at a time in my home and I have a huge back yard for them, and money is no problem. :)