I'm old but pretty new to breeding pure bred, heritage poultry. I have chosen to breed large fowl Cornish after first buying them to try as cross in my blue/green egg laying, dual purpose bird project.
I followed the advice of an old timer and keep them on grass so as to keep live breeding ability high, and have had no problems with fertility. The cocks and cockerels have even been able to live breed the narrow bodied Ameraucanas. They are not suited well to pasture range, and their slowness makes them a target to predators. I've found that covered, movable pens backed with electric fencing to keep predators from burrowing in or reaching through the fencing to be an absolute necessity.
Low hatch rates have been a problem though, and I suspicion that the shape of the eggs, which often lack a pointy end, is playing a part in this. Too many chicks die right at hatch day without even pipping internally, and some have pipped towards the middle of the egg and then drowned. Low egg counts coupled with poor hatch rates can really slow progress in building a flock.
One really big problem is just finding quality large fowl Cornish; too many have crossed them with hatchery type or other breeds in an attempt to increase their numbers. There are also many trying to pass off these crossbreds or those originating from hatchery stock [which are crossbred in my opinion] as the real thing. There is the added problem of those that cross varieties, so the WLRs and Darks sometimes lack the genetics to produce proper patterns or color.
A young WC cock I was told is from pure Herring stock.
A DC cockerel.
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A pen of mostly white chicks I bred from the WC cock, those with dark leaking being from DC pullets. I was surprised to find that WC cock has one copy of dominant white.
