Brine shrimp are both ovoviviparous (o·vo·vi·vip·a·rous) and oviparous. Ovoviviparous means that their eggs hatch within the uterus producing live young. Oviparous means they give birth to eggs which hatch outside of the body. Brine shrimp do not get to make this choice, as it is dependent on their environmental conditions. If the conditions are right their eggs will hatch in utero, if the conditions are inadequate they will lay eggs which can hatch at a later time, up to a thousand years!
This video below shows the different life stages of brine shrimp as they move from eggs to adults. You can see a clear difference between the male and female brine shrimp once they reach the adult stage. The males have these large claspers by their head (as seen at minute 2:05), where as the females have large brood (egg) sacks near the base of their body (as seen at minute 2:30). It is easy to tell them apart when they reach adult hood as you can see at minute 3:15.
For more information please visit: https://wildlife.utah.gov/gsl/brineshrimp/babies.php