Thank you so much. The chick which I am advised came from the buff mother is the middle chick in the photo I shared. That's a problem for all three chicks, isn't it!?I agree that Buff (Silkie) father and Light Sussex or Coronation Sussex mother should be sexlinks, with buff/gold/brown females and silver feathers/white or yellow down males.
Buff Silkie father and Buff Sussex mother should produce buff chicks of both genders.
Any chick with white feathers must be male (white/yellow down.)
If the breeder knows exactly which chick came from each hen, then chicks from two mothers can be sexed.
But make sure to check which chick came from the buff mother--it could be either gender but MUST be buff, so if the breeder says a white chick came from that mother, then there is a problem somewhere.