I have actually found that not to be true (with my stock anyways) I have two very light chicks and two very dark chicks. One of the dark chicks had the dot but none of the light ones did and they are both going to be roos I think. Even when you are breeding these gems, I don't think you are getting "gem" chickens. You are just getting variations of them. I look forward tot he coming years when more people are breeding them and we are getting full grown chickens out of them. I think then we will understand what they need to be bred with to get the sapphire gem look.