how many are there? if there is 4 than all are females. some I can't see the rear, but males of the silver should have red vent feathers, and the 2 black and white are females for sure, that is a blue breasted coloration... my male is the same color exept the male version.
The second one kind of looks like it has a bib, but then it also has stripes on the belly which males don't have, and the bib doesn't seem to be fully formed, so I'm leaning towards all female as well. Though I'd probably grab both silvers and turn them upside down to have a look at their vent feathers - any hint of pale pink feathers would indicate they are male. The other two are red breasted females.