Sharon is right. Shrimplets hatch out from mum's tummy
Possible reasons for the abortion:
- the shock of being transferred.
- first time mums sometimes abort their eggs. Things will improve as they gain experience.
- your male is still too young (I recall reading in another forum about this)
Your females should be able to carry eggs again very soon anyway. I'm sure Sharon will agree with me on this
Do you know how long they had been carrying the eggs? If the eggs are near hatching time, it is possible to keep them until they hatch. I have done it before with some success. I keep the loose eggs in a small tub of tank water together with some moss or plant clippings and float it in the tank. Change 50% of the water with clean tank water every day and see what happens.