"Smokey" is the name of the gene that causes a blue pigeon to look like this . The big indicators are it darkens the feathers and can smudge up the bar and cheq pattern ,but it will lighten the colour of the skin/beak ect . It will also get rid of the "albescent strip", which is the white strip on the outside of the two outer tail feathers . It is also known as Schalie and/or Slate in some fancy and racing circles . That's interesting read,thanks for this Dublin Boy.