Think of chicken colors as color-by number. Pattern genes determine where the colours go, and they only allow certain colours within the outlined areas. Those colours can be modified, but they're the same colour. Lavender is a modification of black, and so-on. Different pattern, but same colours? Completely different-looking bird because the colours are in the wrong places. Or possibly not even allowed in that color-by-number pattern.
Barred Rocks are black in pattern (E/E) and also black in colour (bl/bl). They have an additional gene that's sexlinked and removes pigment in stripes. Because it's sexlinked, hens only have one copy of the gene. (B/-) They're not mottled (Mo/Mo)
Swedish Flower hens should be Mille Fleur. That's partridge pattern (e^b/e^b) and they've got the black gene (which is important because the gene dominant white (I) would fill any spaces where black should be) and they're mottled (mo/mo). They're not barred. (b/b)
Black pattern is dominant to partridge. Chicks inherit one E from mum, one e^b from dad, and the E defeats the lesser e^b! Extended black pattern wins!*
The only color that the chicks can inherit to fill the open space is black. A generic bl from each parent gives you (bl/bl.) yawn
Now here's where it gets interesting.
Barring is sexlinked. Momma has two different chromosomes (WZ), daddy has two identical chromosomes (ZZ.) W is shorter than Z. Because of this mishap, W does not contain as many genes as Z. (And yes, with humans it's the opposite. Remember, guys are the way they are because they have fewer genes than girls do.) One of the genes W is missing is the barring gene.
Henny Penny passes some Ws, and she passes some Zs. The chicks that inherit Zs are male (because they've also received one from Chanticleer making them ZZ and therefore male) and the chicks that inherit Ws are female (they too have inherited one of the generic Zs and are therefore WZ. Female.) W doesn't contain barring. Her Z does contain barring. The males inherited the Z with barring, and are barred. The females are not barred because dad was boring and didn't have interesting dominant genes.
Disregard mottling. The superior dominant genes of the non-mottled hen overcame it.
So your chicks are basically black. The males just happen to be zebras.
*allowing black or any colour that takes the place of black to solidly cover the bird. Lavender, Chocolate, Dominant White, and Blue all come to mind.
It's two-thirty and I can't sleep. If this doesn't make sense, please notify me so I can delete the post, because I'm not up to checking it over at this point.
