Hi Hog, sorry to say there's not a lot of hope for rehoming young cockerels, especially at this time of year when there are so many available. If they come from really excellent purebred breeding stock, they can sometimes find a home in a suitable flock, once they're considerably more mature than 13 weeks, but unfortunately even this isn't always the case. Quite honestly, what do you think a rehoming centre could offer them, when so few people keep any cockerels, and those who do are usually hatching and breeding their own birds from carefully chosen stock. If you do get offers from people or organisations you don't know personally, be very careful where you let them go, as many cockerels 'rehomed' as Free to Good Home end up in very bad hands. Cockfighting is still alive and well, though illegal, and there's a demand for young birds to use as bait to help train the fighting cocks,
Im afraid that a surplus of male birds is inevitable if you want to hatch chicks, and the hard fact is that one just has to face up to the need to learn how to cull them, preferably when they're big enough to eat and thus have enjoyed a good life, though a short one, and have come to a useful end.