Put up signs in all the stores around town- free roosters to good homes.
Just kidding. Mixed breeds are variable in colour, even at that age. Wait till you know who truely are the roosters and cull.

If you end up with ONLY 6 cockerels out of 14 chicks, consider yourself lucky. I've never had a hatch with more pullets than cockerels. You MAY be able to give away some of them, but it does not solve your problem.

There have been a number of threads about this issue lately, and you should take a look at them. Like everyone who is raising "straight run" chicks, you will have to find the solution that suits you best.

As Mountain Man suggests, the most practical solution is to cull the cockerels young roos - and eat them. They are very good eating. The meat is firmer and tastier than store-bought chicken and if you are unaccustomed to it I suggest you start with something simmered: a lovely pot of chicken and dumplings, for instance.

Some people have problems with eating "chickens they know" and others simply do not want to do the killing and processing. You can generally find a processor who will take care of that, but for small numbers it is likely better to learn to take care of it yourself.

We raise Cornish Crosses for meat. Their complete life-span is only 6-8 weeks. You can certainly tell which are the roosters at about 4-5 weeks because they are doing their little rooster dance. They are doing the "stare down" at other roosters and jockying for top position. It is cute to watch and if you want to cull them, it is very easy to tell them from the hens. The hens are cuddled in a circle gossiping and clucking. They act totally different.

They are wonderful oven-stuffers at 8 weeks and very tender and juicy. At that point the Cornish Crosses will be around 6# and other varieties will be less, but still just as tasty.