Nice Thread. I have been raising dual purpose birds for a few years. There are a couple things that make the dual purpose for meat a good and sustainable choice for us. We are already involved in breeding several breeds and sell a number of products that more than cover our costs. We sell eating eggs year round, and sell hatching eggs in late winter and spring for $$, day old straight run chicks in spring and pullets year round. We chose breeds that are dual purpose and somewhat on the rare side so the hatching eggs, chicks and pullets command a good price from backyarders and fanciers. Our meat birds are sort of a byproduct of the operation. I end up with a lot of cockerels every summer, more than our family can possibly eat in one year. I end up having to grow out a large number of cockerels to 20 to 24 months to select my breeders for next year. These boys day range and forage actively. Right around this age they make excellent eating. and we get great eggs year round. I butcher a few at a time. There are downsides to this approach of course. The commitment to time of raising and breeding is not for everyone. The roosters do start harassing the hens much earlier than 24 weeks so I like to keep the cockerels separate once they start acting up. There is a lot of crowing. The processing is not as easy as Cornish cross broilers, dark pin feathers etc.
The flavor of the dual purpose breeds is excellent, I personally prefer more dark to light meat and love roasted chicken. But your buyers must be informed about the product so they don't treat it as a store bought chicken in the preparation and cooking.
I have created a demand among my friends for this delicious home grown chicken and cannot meet the demand with my casual kill a few roosters a week habit. So I am thinking of trying some of the Freedom Rangers this summer in a day range management setup. This thread has been very helpful.