While the SFH is a landrace breed, keep in mind that landrace does not mean there was no human intervention. The SFH was not a bird that developed living in the wild (like the Sumatra) but a breed that developed on farms throughout Skane. Just as you and I do, those farmers kept their favorite birds and ate the cockerels they weren't as enamored with. Because these birds were used for both meat and eggs, chances are the larger cockerels were kept for breeding as the extra male offspring of those birds would yield more meat.
Conformation plays a BIG role in the health of a bird. Breeding a cockerel with a low-set, too-high set or pinched/narrow tail will produce a generation of pullets that have egg-laying issues. Look for boys with a well-set tail that has a wide spread to it. His pullets will be able to lay bigger eggs for a longer time.
Look for boys who appear wider than the others when looking at them from above. From the side, look for the boys with the deepest, roundest chests. These traits not only produce cockerels with a higher meat yield, but are less prone to heart, digestive and respiratory issues because there is adequate space inside the ribcage for healthy organs.
Look for birds who do not have split wing. (You can Google images of this negative trait where the first primary feather is absent or set too far from the secondary feathers.) This trait can mean that free-range birds have less ability to escape from predators and less "parachute" when jumping from a high perch (which could result in leg injuries).
And if you or your son think you'd ever like to show your Swedes (they can be entered in many shows in the Rare Breeds group), look for birds without comb sprigs, that have plenty of flowering and with good personalities.
Trust me - even the Vikings and country farmers in Skane put plenty of thought into what birds they kept and what birds they consumed at a young age. Their livestock were pivotal to their existence, and they knew well the signs of the healthiest birds that would both lay well and produce the best meat.
