Shelter workers will likely tell you that black dogs, as well as black cats, will not get adopted from the shelter as readily as other dogs and they are more likely to be euthanized. There are some studies that show the opposite is true but since there is not any data pointing toward the scientific facts, I would be likely to trust the people who actually see it for themselves, the workers at the shelters.
To read more on this story, click here: Black Dog Syndrome: Why Black Dogs Are Less Likely To Be Adopted