I do plan to sell them at very low prices online. I also have a few connections in the area of people that raise meat chickens all natural, and generally don't get Cornish rocks. So hopefully they would purchase them for dirt cheap prices. And I would be able to kill them if need be.
If you plan to hatch 5300 birds a week that is over 2500 males a week, I'm betting you will saturate the local need for slow growing broilers within days so I would not consider that much of a viable outlet, even less for bantam roos... Most hatcheries end up giving males away as 'packing peanuts' because at the end of the day it's actually the better investment vs killing and disposing of them... And when I say better investment, consider that if you toss 5 males into every box of 25 it's only a few pennies of insurance that can easily be justified and recouped if it saves just one 'paid for' chicks life in that box... The price paid by fertilizer and pet food companies isn't worth the effort unless you manage to find a real sweet deal, you are probably looking at literally a penny or two a chick if that...
Another option that I know of to get a very small return from the male chicks something that most hatcheries don't bother with as it's a hassle to make pennies, is to freeze them at day one and sell them as feeders to reptile owners, zoos and other wildlife agencies... Several large UK hatcheries do this but there isn't much profit, in the UK they sell for about 5 cents a chick in low volume bulk...