My sumatra are all just hatchery stock from ideal in Tx, only one of the hens would I breed forward, all the others are just pet quality or culls were a breeding for show quality. The heritage breeds usually go way back into the mid to late 1800's when people had to be self sufficient, so they tend towards being good "setters" broodies and free rangers because of the natural and selective pressures they had to face. Sumatra eggs look exactly the same as silkie eggs but tend towards a slight pinkish tint. They would be compatible with silkies. I would definately skip the roosters from them because well none of mine survived their teens and I almost lost an eye to the one I thought was going to make it in to adulthood. Moody adolescence and in springtime for the roos.