I didn't realize you hatched out the production lines that you have. I always pictured them arriving at your farm in a box ( the ISA's). I missed having eggs during the fall, so I am trying to figure out how to fill that hole, or reasonably fill that hole.If we hatch out production grade chicks before Memorial Day, which we do, yes, they will all be laying by Thanksgiving. That is why one has strains like this. Their purpose in life is egg production. If such birds are not in lay, and their leg coloring and feathering displays whether or not they are in lay, they serve no purpose and are culled before Christmas. No if, ands, or butts about it. This is a farm, so that's just life out here.
The heritage fowl hatched in April and May are NOT expected to enter lay until the following February and won't be judged negatively until March or April. The old line Barred Rocks take 32 weeks to come into lay and the old Rhode Island Red lines take 30 weeks as well. The roosters cannot be judged as to their worthiness until they are almost a year old. The slow feathering, slow growing, slow maturing aspect of standard bred, heritage line birds is such that there can be no hurrying. Hope that helps.
By the next fall, only breeder stock of the heritage fowl is fed through the winter. All I need is two males and 3 or 4 females. That's it. From them, over 50 chicks can spring. Economics play a big part of a successful homestead.
Rocks are a long time to mature as I remember, helps in keeping the feather pattern correct; real barring. ANd no history of being a strong winter layer, as I make sense of this. When you reduce the number of BR for the winter, do you always keep some pullets and a cckl, or does that depend on what grew out of the 50 chicks?