Most certainly females - When my brahma girls were young, I really could swear that a couple were male. I thought that because their tail feathers started to curve, and that their legs being huge were certain signs - But they were girls. These girls are definitely not roos - A brahma cockerel will have a deeper chest, very long hackle feathers, and definite long, stringy saddle feathers with a much more droopy set tail. These here just look like hatchery-type females.
Funny - Mine looked like that group pic too - One was very white, one had a lot of fine lacing in the feathers along the back, etc.