Welcome to Backyard Chickens, I agree with ChemicalchiCkens. The wrong kind of customer is usually looking for free birds, for BAD reasons. Charging some fee for the unwanted roosters helps eliminate them. You will also get inquiries from those that are looking for a free dinner - if that doesn't bother you.
Best wishes and have lots of fun! 
and Welcome to Backyard Chickens.
to have you here with us. Enjoy your time here at BYC!