The University of Delaware Agricultural Extension also breeds and releases eggs each spring, and some of the eggs are Delaware Blues. I had two - one male, one female - last spring. The male was extremely aggressive and I traded him to a friend with a farm and a bossy Blue (from the same source) who could handle him. The UD Extension does breed pure-bred lines for research purposes, and these come from that via the 4-H program. My understanding is that this is probably the largest population and source of Blue Hens anywhere. (UD's mascot is the Blue Hen and they have a vested interest in maintaining the line. It's not a recognized breed, though, and they were bred for fighting, so they tend to be very beautiful but very mean birds and I don't think there are really "rules" for breeding to maintain the line. I don't know how they do it.)