kbug,

Check out http://www.happydranch.com/92.html where I found the below information.
Click on 'invertebrates' and pick you choice.

Your worms are likely "hiding" in the layers of bedding below, they are smart? enough to be where survival conditions are best.
Good luck.

TC

Earwigs are large predators, easily seen with the naked eye. They move about quickly. Some are predators. Others feed chiefly on decayed vegetation.

Earwig Trap
A simple trap can be made using a tuna or cat food can. Add 1/2 inch of vegetable oil and place them around the garden. Dump and refill with oil as they fill up with earwigs. Another trap involves a moistened, rolled up newspaper. Or use short pieces of bamboo or hose. Place these traps on the soil near plants just before dark. Earwigs have a preference for tight, dark places, and will crawl into the tubes and stay there. In the morning, shake the earwigs into soapy water to kill them. Continue this procedure every day until you are no longer catching earwigs.

Beneficial nematodes have proven to be helpful in the control of earwigs.