Did these chicks come from a hatchery? How old are they?
First looks like an Easter egger
Second could be an Australorp, need better pic to confirm
third is a barred Rock
Fourth--I don' think it's a buff Orpington, it looks to be feathering in white. White Rock maybe? what color are legs?
fifth--could be an Easter egger, what color are the legs?
sixth--some type of hatchery Red bird.
Can you get pics of the white and grey birds' legs?
Maybe a pic of the grey bird standing on her own, to see her body shape. I was actually thinking Orpington for her, but she looks to have muffs? Puffy cheek feathers? That's not something Orps should have, so I went Easter Egger.
With a large operation, there's also always the possibility they could be mixed breed birds, something to keep in mind.
1st one is an Easter Egger.
2nd one is probably an Australorp.
3rd one is a Barred Plymouth Rock.
4th one (if it has puffy cheeks/muffs) is probably an Easter Egger or possibly a White Ameraucana.
5th one could be some sort of Orpington or Orpington mix.
6th one is a hatchery-quality Rhode Island Red/production red.