Svarthona x BBS Ameraucana, what to cross for more size?

[annagoodspeed]

I am trying to develop a dual purpose fibro bird. So far the Svart Hona cockeral has crossed with the BBS Ameraucanas, and it looks like the fibro is being passed consistently.
I have Langshans, but this season it looks like both cocks are shooting blanks, possibly due to crd, ( father and son, a culture showed it as Lecleria and negative for MG). Before I replace them with more Langshans, I wanted to ask if that breed has the right genetics to carry the fibro through. They have slate legs but with pink feet bottoms, and I am not sure if I understood the thread that discussed which leg color to use breed wise for fibro. Can anyone suggest the best large fowl to cross, with the idea of more body size being the next most important factor? I would also like to stick with the bbs coloring to limit the results, if possible.
Here is a pic of what I am getting, although these cockerals are in that awkward phase, just started crowing. Not especially ravishing, haha.

 

[nicalandia]

How about crossing them to Black Jersey? Any large breed of chickens with slate shanks will give you both genders Fibromelanotic birds.. if you cross your Fibromelanotic rooster with a yellow/white shanked hen only your pullets will yield black skin. but you can take the F1s roosters and mate them to F1 pullets and take if from there

 

[annagoodspeed]

That opens up the field considerably! There was a post in an older thread that was talking about the color of the bottom of the feet, and I took it to mean that if there was white or yellow they would not express the fibro trait. The Jersey Giants have slate with yellow bottoms, so the Langshans with slate/pink should be ok too if I replace the cockbirds?
Thanks so much for posting Nicalandia!

 

[nicalandia]

There was a post in an older thread that was talking about the color of the bottom of the feet, and I took it to mean that if there was white or yellow they would not express the fibro trait.

The only chickens with black on the bottom of the feet are Fibromelanotic breeds like Silkie/Cemani/Svarthona, all other breeds will have either yellow or white.

The Jersey Giants have slate with yellow bottoms, so the Langshans with slate/pink should be ok too if I replace the cockbirds?

Yes, Langshans will work for you.

There has been many people working on Fibromelanotic Meat breed projects, I have yet to see one finished, but I can't see why it could not be accomplished, Starting with feed restricted Broiler hens(restricting feed to keep them from getting obese) and using Fibromelanotic rooster over the hens, this will produce a Fibromelanotic F1 females and regular Males

 

[annagoodspeed]

Thanks, sometimes I amaze even myself at the denseness of my grey matter.
It would make sense to use broilers for a real production bird. I am going for personal use, and I like the idea of sticking to the same bbs color genetics with the crosses, and also ideally getting some cold hardier comb modification. Not too sure about the seemingly dominant muffs amd mukluks, but who knows?

 

[annagoodspeed]

So, this season produced fibro crosses with both breeds, as you said, Nicalandia, thanks! Now for culling cockerels...Should I keep any F1 cockerels, or just keep the original cockbirds? I did get a few Langshan crosses, so I was thinking to keep the original cockbird plus the original Svarthona. I just have Ameraucana hens, no cockbirds. I did get some Langshan Svarthona cockerels, and they look to be significantly bigger, with a smaller comb.