You could buy more worms... but they are expensive starting at a low $20 a pound not including shipping that only gets you 1000 medium sized worms. That much eats around a cup a day.

You probably have a lot more than that hiding in the manure waiting for conditions to improve. You should have a lot of worm 'eggs' in there too. They wait to hatch in wet conditions.

A couple of good web sites:

Red Worm Composting; http://www.redwormcomposting.com/
The site is ran by Bentley he is a worm expert. Has a collage degree on the subject. He gives good advice. But sometimes takes a week or more to get back to you. He is also a commercial worm grower.

Vermicomposters; http://vermicomposters.ning.com/
This form has commercial growers as well as newbie hobby members. You can find Bentley as a member on this form as well. This form is a little easer ask questions on. And you get the advantage of a lot of people who can give answers to your questions.