I have 5 new baby zebra fledglings!!

1. At what point can I tell which are male and female? All look like hens so far.
2. Also they all seem to have a poopy looking area on their vent. Haven't seen any runny looking droppings so far. Is this normal for the fledglings?
AND, we also have 4/5 quaker fledglings so far, this is very unfamiliar territory, on a learning curve!
