I worry about people wanting them for cock-fighting purposes if I just sell them on Craigslist. How do you weed out the nutjobs?
My approach, however I sell/rehome/give them away, is that once they have left my hands I no longer have control over them, and I have to make my peace with that.
Someone could reassure me they'll keep the cockerel as a beloved pet and perch it on a gold throne and feed it caviar, and then as soon as they leave, they could kill and cook it or do whatever unspeakable things. I will have no knowledge or control over it.
As much as you'd like to vet prospective new owners, it just isn't possible if you want it to take weeks rather than years to get rid of these cockerels. And you have plenty that need to be rehomed!
It's a cruel aspect of chicken keeping (on us and our emotions), but dealing with surplus cockerels is part of the package. You can only ensure they lived a happy life when they were with you. Anything else is out of your hands.
I've been there and it's horrible. Sending hugs.