They are likely Red Sex Links, which are produced by crossing a red gene rooster with a silver gene hen. The chick's gender can be identified by color at hatching (males are whitish, females are reddish) and this color distinction remains with them until they are adults (roosters are white with some reddish brown feathers in the saddle area, hens are reddish brown with white underfluff). Red Sex Links are marketed under a lot of different labels by hatcheries including a number of labels with the word "brown" in them, including Brown Sex Link, Bovans Brown, Isa Brown, Shaver Brown, Babcock Brown, etc, but no matter what label they are marketed under, Red Sex Links are egg laying machines, outlaying either parent breed. It's one of the interesting quirks of hybridization. Assuming your "Browns" are Red Sex Links, you will get loads of eggs. Good luck with your flock.
