Many Double Merle dogs come from disreputable sources, such as uninformed back - yard - breeders or puppy mills (none of which are concerned with the health of the dogs they breed or produce, or the emotional impact on the unsuspecting families purchasing those dogs). (lethalwhites.com)
In 1840, cattle farmer Thomas Hall decided to crossbreed blue merle dogs, probably of the Collie or Old English Sheepdog type, with tamed dingoes. (animalwised.com)
Almost all iris colobomas in Aussies were seen in merle dogs, however they will occasionally be found in non-merles. (ashgi.org)