I totaly agree, $6 is very fair. Tell him to pay up or hit the bricks. I suspect he intentionaly left them there that long so you would have done all the "hard work" for him. Man i hate it when people are like that.
if he has a prob with the price refund his money if he hasnt gotten the chicks already. and send him on his way. i cant stand people like that! and that is a cheap price considering what feed is going for