First - it would help to know what class subject it is. The activities/worksheets would be different for say, math (you could count them. "Vun 'ermeet crab ah, two 'ermeet crabs ah ah...") versus science.

Otherwise, I think you should check out these sites:

thecrabbagepatch.com (I *love* them. Buy all my hermy stuff there)

hermit-crabs.com

hermitcrabassociation.com

and landhermitcrabs.com

A lot of people are under educated when it comes to hermits, and I think it's best to make sure your crabitat and living conditions are perfect before you even think of stressing the crabs out in a school environment. Not saying anything bad about you since I don't know how you keep your crabs. But I wanted to spread the word.