The BR, at least mine, are very slow to feather and mature. This is my cockerel at around 7 1/2wks. I need to get some more photos.
It's been a challenge for me in finding a lot of info on the Stukel and Good Shepard lines. But from what I gather, this combo is slow to mature and in cockerels especially it takes a good year to see development. Again, it depends on your goals. Mine
is to have a slower maturing bird, especially in pullets/hens to see if later maturity decreases reproductive disorders and cancers. It may not make any difference and only time will tell.
If you are looking for a hefty, fast maturing bird for butchering, then these BR may not be what you want. I do feel like they will be a good size when mature, but they won't be a good butchering size at say 16wks.
I still have a lot to learn and am looking forward to see how they turn out.
One bit of interesting info I found
http://featheredreptilesfarm.weebly.com/barred-plymouth-rock.html
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