Don't sell them. You'll just be contributing to the thousands of dyed chicks sold as easter gifts or to apease whiny kids that later die or are disposed of. People who love chickens accept that they are the color they were meant to be.
I don't like coloring chicks becuase it makes them look like toys and most of them end up dead in a few weeks. You can color chicks by injecting the embroy and covering it with wax till the egg hatches. I don't know the exact steps so look it up, but make sure you are selling it to some one who...