If your BRs were pure (that is no other stray genes like a gray or naragansett), then your offspring this year that have one red gene are genetically very similar to your original BR X wild, and have one red gene and one not red. The two that look like Bourbon Reds have two red genes. Your ratio of 2 to 13 is a bit odd. It is very unusual to be that far from 50/50, but obviously it happens now and again.
If you can see a difference between the first and second generation birds, it may be because there are other domestic genes that are replacing wild genes that can affect colors, and you are getting closer to the domestic red bronze. But you should not expect to cross a red bronze with a bourbon red and get something in between. The offspring will all be red bronze or bourbon red.
If you can see a difference between the first and second generation birds, it may be because there are other domestic genes that are replacing wild genes that can affect colors, and you are getting closer to the domestic red bronze. But you should not expect to cross a red bronze with a bourbon red and get something in between. The offspring will all be red bronze or bourbon red.