I remember I had one or two that looked like that after foraging all day. The elders called them (loosely translating here) speckled girls. Which is weird because they weren't speckled. They were blue, the colour of a Blue Haze. Supposedly these were the best foragers. I didn't find them to do better or worse out in free range. What I do remember is that they were treated as social pariahs by the rest. They were always a little bit removed from the group