When we lived in the Hayward Calif area we visited Sulphur Creek many times. They take wonderful care of wild injured animals. I don't believe that there is a cost
Here is the web page link to check it out further.
http://www.yelp.com/biz/sulphur-creek-nature-center-hayward-2
Sulphur Creek Nature Center is a wildlife rehabilitation center that is also committed to education about animals. It's free to visit. There are owls, ducks, spiders, snakes, fish, a coyote , chinchillas and many more animals. They have nature programs and day camps that do cost money and are scheduled through HARD (Hayward Area Recreation Department) You can even have your birthday party here! There is a lovely little park with tables and BBQs.
We have had a birthday party here and it was a hit! The party was for my daughter's 2nd birthday. She loved it. It's a great place that small children and older children will both love!