Excellent- btw just saw your comment on naming the birds. Most of mine are not named, however I 'know' all of them and can mentally trace the ancestry on many of them. But, I sure do see an advantage of naming them to function as ID- lineage, the carcass, etc.
Your pairing proves your white rocks have barring, most likely used as a way to clear their legs to yellow(would have been green without barring present).. and any repeat breeding of non barred to your white rocks would be a sex linked mating- white dot on chick heads= cockerel.
The big surprise is your white rocks aren't genetically black. Nearly all commerical/production bred whites are genetically black chickens.
forgive me for not saying so earlier but thought it was obvious- beautiful birds!