Also Welsummers lack Columbian like RIR or Buckeyes, columbian seems to have little effect on chick down, but perhaps it does when sexing using the Welsummer method at least on the RIRThat is strange. Welsummers-with their red duckwing pattern- seem to have sexual dimorphism from hatch. I accidentally crossed a LF Buckeye (light down) with a Welsummer and it appears to be female so far.
I am curious to see if your friend's issues are rooted with the very dark down strain.