Hi Swamp,
The question I see is, can docility be bred into the birds with little effect on size and growth?
I belivie docile birds are made and not inheredity. I say this because the way the chicks are reared.
I once had to place my brooder of 50 chicks in a different place from where I normally did. These chicks only saw me maybe twice a day to put food and fresh water in. So by the time they were ready to move on, they were very wild and flew out of the brooder when it was opened. It was a two man job moving them.
My brooders now are kept in a place where people and animals noise etc is common. These turn out totally different, tame and quite very easy to handle, weigh and to photograph. Even as adults these birds rarely try to escape, if they do they are very easy to pick up.
The point I'm trying to make is, the above two batches were from the same breeding group of 1 male and 4 female normals.
So if your starting from the begining, my advice is to just rear the birds docile and select the largest males from one batch and the largest unrelated females from another batch. I'm not over keen on inbreeding, because over time they lose size, fertility, hatcherbility of eggs produced.
This is the way I do it, other peoples idea's will be different.
Ironsun.