i raise any culls to 8 to 12 weeks and then its freezer camp. with some silkies and cochins ive had in the past, i will put up a lil sign at the local county agents office ( for the 4-H) kids. Those 2 breeds do well with calm children. Also, several people i know like cull silkie hens for thier broodiness.
Langshans take a LONG time to decide when to cull. I'll either eat the culls, give them to friends or family who are not interested in showing or keep the females in a laying flock. Right now I have a cute little pullet that has okay type but is way too small for anything I'd be using her for.
I think you are wise to plan ahead. I don't know your planned breeding program, but I'd be surprised if you keep as many as one in ten. I'd also be surprised if you can eat that many chickens. Besides, it gets expensive feeding them until they get that big, plus all the room you need. You may not feel comfortable with some of my ideas, but you don't have to accept them.
You could call the local zoo or maybe a pet store. Do they need young chicks to feed snakes or other animals? Maybe larger chickens for big cats or alligators at the zoo?
Does someone in your area make organic compost You probably won't have enough to interest them, but it is better than wasting them.
Other than selling or giving them away, that's all I can think of. Good luck with your breeding program.
Do you have a sale barn you could take them too? or even just put a sign at your driveway _day old chicks for sale? I would try to find them new homes rather than kill them. Set up in your front yard. Call your feed store and ask if you can set up a table?
craigs list, and fliers at petshops, vet offices, etc.... you can advertise them for pets/layers, but you can also advertise them as feeders for people with snakes or other herps. Raptor centers are another option as was said already, but the ones near me only buy from the kind of places that produce laboratory animals, for fear of bringing in diseases. If its going to be a regular thing, you might set up a long term relationship with a snake/herb breeder etc. so that advertising and meeting with buyers isn't a job you have to keep on doing.