Sometimes you get black sexlinks that hatch not black but dark red with lots of penciling when older. 1 in about a hundred or so hatch that way. So that might still be a black sexlink, but it dipped into the red gene pool a bit stronger then others.
When I use to order lots of black sexlinks from the hatcheries I use to get 1 or 2 dark red ones in every batch, being a mixed breed you do get the genetic oops now and then. Your pullet looks like a red "black" sexlink to me.
When I use to order lots of black sexlinks from the hatcheries I use to get 1 or 2 dark red ones in every batch, being a mixed breed you do get the genetic oops now and then. Your pullet looks like a red "black" sexlink to me.