They look to be Red Sex Links...and both look to be pullets as you would expect, so I think first generation Red Sex Link (which are color coded for gender that first crossing).
And yes,they come by many names...ISA Brown is one, Red Comet, Gold Star, Red Star, Cinnamon Queen, Red Sex Link, Gold Sex Link.
It is a hybrid (mix) of a red based rooster, usually a RIR or NH, and a silver based hen, usually a Silver Laced Wyandotte or Delaware or non-dominant white Rock.
The different mixings cause the different names, as hatcheries use their favorite formula, but it all means one thing...color coding in the chick down for gender.
At hatch, females are foxy red or yellow with red highlights while the males are pale yellow. This is valuable for hatcheries as most people want layers not roosters.
RSL hens grow out to be red hens with white trim while the males will be predominately white with some red bleed through usually at the wings.
But that only works with the first generation crossing with a purebred red male over a purebred silver based female. You can't breed 2 RSL's and get sex linked coloring in chick down. In the second generation both genders are red with white trim (red-gold as chicks).
Which is why the one poster pondered if it might be an RSL in the background. Typically with an RSL in the background of a "mutt" mixing, you end up with more white in the birds depending upon what the other parent was...but it can be very deceptive of some unscrupulous people who pass off second generation RSL for gender identifiable first generation RSL by breeding an RSL to an RSL.
Since you got a grab bag of surplus eggs from a hatchery, I wouldn't doubt they are RSL...and at this age definitely looking to be standard sex linked RSL pullets.
Edited by Lady of McCamley - 3/3/16 at 7:39pm