Other options are getting a vet to caponise them (basically neutering them) or giving them to someone who will slaughter and process them for meat, hopefully humanely. I couldn't do that with a pet myself, but many chicken keepers raise and process their own food this way which is fine.
Some...
it kind of makes sense as to why the previous owners just abandoned them, doesn't it. So cruel and irresponsible.
They are lucky boys indeed that you've rescued them and if you don't keep them, you will try and rehome them responsibly.
You've got a lovely bachelor bunch there. I'd keep them and just buy eggs at the store!
If your neighbours complain, then you may need to rehome them, but if they aren't actually complaining then you haven't got a problem (yet).