They need a M/F pair, with no real way of sexing them. Not sure on number babies. I started with about 4 or 5 and ended up with 40 or so total, but I'm not sure if it was 1M/4F, 4M/1F but a few of those tanks are low low pH tanks for crystal shrimp, so their rates may be a lot lower as snails usually like a higher pH tank, higher gH (calcium) tank.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.
Sump Pimp #2
My Tanks and my shrimps