Glad you've found us, RoseAnne, welcome.
I have a compost pile (only about 6 months old) where I add kitchen scraps and leaves. I have worms at the moment. I moved this pile from anther location in my yard that seemed to be conducive to worms in summer. Few, but they were apparent. That location was on the east side of a north / south facing block wall with lots and lots of shade and needed moisture. What sort of exposure do you have? It might have something to do with whether you can keep the worms active. If not, I'll tell you we've had this conversation before and it appears that the worms do migrate *somewhere* and reappear during cooler weather. I think it might depend on the exposure of you pile, however.
Maybe some others will drop in and add more wisdom; Kelly, Jayne, Jill, Dete, Dan etc.