I gave a friend some eggs to hatch under her broody hen and she hatched all 4. Since then we've been trying to figure out which of my roosters is the dad. One rooster is a Double Silver Laced Barnevelder and the other is a Cream Brabanter. The moms are Barred Rocks and possibly 1 Jubilee Orpington (I thought it was her egg but not sure now due to coloring of the chicks). Three of the of the chicks are pretty much all black but have slate legs like the Brabanter and 1 has yellow legs like the Barnevelder and is very clearly of Barred Rock decent. Pictures of two of them for reference (the other ones look just like the black one). Thanks in advance!
I am pretty sure that all chicks have a Barred Rock mother. With either rooster, she would produce sons that are black with white barring and daughters that are black with no barring. Jubilee Orpington hen should not produce those colors of chicks with either rooster.
I think yellow feet on the cockerel make it very likely that the Barnevelder is his father, but it isn't 100% certain unless we could prove whether the Brabanter carries the yellow foot gene or not (Brabanters are not supposed to, but that doesn't prove they never do.)
I would look at the soles of the pullets' feet. Yellow soles would strongly suggest that their father is also the Barnevelder, while white soles would be proof that the Brabanter is their father. Barred Rock (yellow) and Barnevelder (yellow) can NOT produce a chick with white soles on the feet.
In the pullet picture, I think I see a bit of leakage in her breast feathers (a bit of color that is not black.) If her father is the Barnevelder, the leakage should be silver (white). If her father is the Brabanter, the leakage should be cream or gold. Unfortunately cream and silver may look similar enough to be confusing, so this may not actually be helpful for sorting them out.
Other thoughts about foot color:
There are about four genes that might be interacting here, so I'm not exactly sure how to interpret some of the results:
White vs. yellow skin, with white being dominant over yellow. Yellow x yellow will give only chicks with yellow. Barred Rocks have yellow skin, and I believe Barnevelders also have yellow skin. So Rock x Barnevelder should never give any chicks with white skin. Brabanters should have white skin, but because that is the dominant trait, you cannot be sure if the Brabanter rooster is carrying the recessive gene for yellow skin or not. So white skinned chicks would have a Brabanter father, but yellow skinned chicks also have a chance of having a Brabanter father.
Light vs. dark skin, with light being dominant over dark. This gene is on the Z sex chromosome. If you cross a dark-foot rooster (Brabanter) with a light-foot hen (Rock), you should get dark-footed daughters and light-footed sons. A light-foot father (Barnevelder) will produce both sons and daughtes with light feet, but there is a chance of him carring the recessive gene for dark feet, which would let him produce dark-foot daughters too. Regarding interactions with the white/yellow skin genes: light skin can be white or yellow. Dark "white" skin is slate, and dark "yellow" skin is willow (greenish color.) The dark color usually skips the bottoms of the feet, so you can look there to see if they are white or yellow.
Black feather color often goes with black on the skin of the shanks and feet as well. Something about the feather-color genes can do this, even in chickens that would otherwise have light skin. You can usually tell white vs. yellow skin by looking at the soles of the feet, but may not be able to tell dark vs. light skin.
The barring gene makes white lines across the feathers, but it also tends to make the legs look lighter in color, by removing some or all of the black that would otherwise be there. This is part of why your barred cockerel has such nice yellow legs. Barring is also on the Z sex chromsome, which is why a barred mother gives it only to her sons. A barred rooster could give barring to sons and to daughters, but that is not what you have.
Between the black feather color and the barring gene, I'm not sure whether the pullets actually have dark feet (Brabanter father), or whether their feet are dark because of the black feather color and the lack of barring gene.