Are the ground snakes Sonora semiannulata? I know their range is large, but I didn't know it extended out to Puerto Rico. If so, they will usually eventually take crickets, or some other small inverts. Some will even take to eating prekilled crickets (yes prekilled crickets, usually frozen/thawed). It helps to pull the rear legs if you offer live, makes the little buggers easier to catch. As far as breeding, I believe they need a brumination cycle (I've never tried breeding 'em) 3-4 months at about 55-60 degrees (maybe the population on Puerto Rico dont need temps that low?), similar to most North american colubrids. They are awesome little snakes, I hope they do well in your care.

-Evan

P.S. If they are not S. semiannulata, please disregard all the above info