Blue Double-Laced
A variant of Barnevelder (Gallus gallus domesticus)

Double-laced pattern where the black lacing is diluted to slate-blue by the blue gene, giving a softer contrast.
Keeper tips for this variant
Blue is heterozygous and won't breed 100% true — expect blue, black, and splash offspring from blue-x-blue matings, so cull/select for the cleanest lacing.