She may be feeding them. She willgenerally only feed them 1 or 2 times a day in the early morning andevening. She will basically ignore them the rest of thetime. In the wild this prevents the nest from beingdiscovered. If she is feeding them, their bellies will beround and full (they'll look fat) if their bellies are skinny, sheisn't feeding them.
Baby rabbits are very difficult to hand feed. Try taking momout of the cage and sitting her on your lap. Place the babiesunder her. You can also get her to roll on her side and helpthe kits find the nipples.
There are several threads on here about this problem. I'll try to post some links.
Good Luck!
Jen