FredWell, Cyn, you've made what a few of us have already chatted about. How to make a true Black Rock with yellow legs. That's what you've done here. Although the APA has bantam Black Rocks, the large fowl still await development and acceptance.
I understand the UK does have the Black Rock in large fowl. I'm unsure about other countries.
Congratulations on those chicks. If you put together a bird that conforms to the Standard of a Rock is a Rock. The fact that they are 3/4 is irrelevant. What is relevant is whether they meet the Plymouth Rock Standard and first, they need to breed true. I"d love some!!! Like I need another Rock in my head, eh?
A guy from Cumming, Ga came and bought all my "black chicks" today (13 of them)....they are a result of Jack over Madea (my 1/2 barred, 1/2 Col gal who is black phenotype)....he is moving to Crossville, TN and is going to try to get a "solid black Rock" going....with 13 that are split E/eb he should be off to a decent start. two of the males at 3 weeks old were HUGE. Cyn, if you need any "blacks" I'll have a few more in the next couple hatches
These chicks had a lot of black "wash" on the legs, not yella like Cyns