How long did she have the eggs for? It takes 3-4 weeks for them to hatch.
You probably can't see the babies. If she dropped them today, they are very tiny, clear or near clear and hiding like hell as is their instinct to hide in the moss, plants, substrate, anywhere they can't be eaten. They also need and only eat all the organisms in the biofilm covering plants, substrate, moss, driftwood, etc, so they will stay there as it's safe and full of food.
As they grow, they will venture out. I had a tank that I tore down, took everything out of, drained the water to a few inches, checked and triple checked for babies, got all the ones I could see. Went to work on the tank about a week later, found 14 baby crystals in it. This was a 12" cube tank with everything but substrate taken out and 14 shrimp still hid on me in a few inches of water.