I,ve been looking for DC for a while and from what I red and researched Cackle Hatchery has the best strain as far as hatcheries go. Unfortunately Cackle did not sell any DK chicks this season (2015). I called them asking why and they would not give straight answer, just typical BS "they are not available this year".
As far as Stromberg and Murray is concerned I would not buy any birds from them cause they are just a chicken "brokers" they do not hatch anything. Why buy overpriced merchandise from a middlemen?
From my experience with hatcheries over the last 10 years the best were Cackle, Mrhealthy and Mayers. Ideal was barely acceptable but that is the biggest chicken "factory" of them all.
So I am waiting for Cackle new offerings for 2016 and if they have Dark Cornish available I am going to order as soon as they are available.