How did I get golden lacing in a chick?

[2102Simm]

Allow me to set the stage. I had a wonderful roo that was a White Rock BO cross that did the deed with my pure BO hens. Now many weeks down the road I am presented with these offspring who are both 13 weeks old. Then there's this little surprise guy from my broody hen (sorry for the bad pics, this is also the meanest hen in the flock so I hesitated getting closer). The 2 older birds I know are from my BO girls bc I had the eggs marked in an incubator. My surprise baby is from a BO hen as well bc I took the egg from a BO hen for my broody. Can someone explain how my first 2 look almost solid white with no barring but my broody baby has gold barring?

 

[NanaKat]

I suspect the color comes from your rooster. He has barring in his tail and little darker buff notes on his body.

 

[The Moonshiner]

The white rock was a barred rock under the white. The rooster received one copy of barring from the white rock. That gives him a 50/50 chance of passing it to his offspring. The buff chick got the gene the other two didnt.
Your rooster also is silver/gold. He received a silver gene from the WR and a gold gene from the BO. He has a 50/50 chance of which one of those genes he passes forward. Your buff recieved gold. Your light ones recieved silver.

 

[2102Simm]

The white rock was a barred rock under the white. The rooster received one copy of barring from the white rock. That gives him a 50/50 chance of passing it to his offspring. The buff chick got the gene the other two didnt.
Your rooster also is silver/gold. He received a silver gene from the WR and a gold gene from the BO. He has a 50/50 chance of which one of those genes he passes forward. Your buff recieved gold. Your light ones recieved silver.

Thank you so much! That makes a lot of sense. I don't know a lot about the genetics in birds but I want to learn more. Is it normal for the chick to be displaying such a large dark pink comb at roughly 6 weeks old?

 

[The Moonshiner]

Normal for a cockerel to.