Compost King
Free Ranging
I put a Dorking over a Red Ranger and had great results, I also had great results with Naked Neck over a Red Ranger, had so/so results putting an Ayam Cemani over a Red Ranger (only the females had the black skin/meat). That grey alien looking carcass in my profile was 1/4 Red Ranger 1/4 Ayam Cemani 1/2 Naked Neck. The Red Ranger long keel remained through 2 generations but it didn't flesh out very meaty.I would suggest you begin with a dual purpose rooster over ranger hens and select from there if you want a bird that will act more like a "normal" chicken.
If you can breed Red Ranger to Red Ranger successfully they will act like normal birds. They may even take to foraging faster than your heritage breeds. I believe only Leghorns foraged faster than Red Rangers out of the breeds I had. Everyone else went to the feed first then foraged. The Red Rangers can be aggressive towards smaller birds in a confined area, but if the area is large enough with enough hiding spots they give up chase rather quickly. If I get my hands on a pair of Red Rangers I plan on breeding them and seeing the results. If I were to choose a bird to cross with them for the sake of Genetic diversity I would pick NH reds from Freedom Ranger Hatchery. High quality Buckeyes might be great too. I would use a Red Ranger male over the heritage breed, then only keep the females in the program because that will keep the Rapid Feathering trait. The Males from that crossing would have feathering rate of the mother. If one of them genetics experts corrects me I will gladly submit to their opinion I do not know genetics I only know my own experiences when breeding rapid feathering bird to not rapid feathering birds.
Although mine died semi young and probably never reached a good grow rate due to what ever problem they had that caused them all to die one by one... I didn't even notice them look like meat chickens. the first week they were larger than the rest of the chicks I had at the time but eventually the other chickens got just as big. They really just resembled white rocks. I wasn't impressed. They didn't forage any better than other chickens either. They just ate from the feeder and scratched for feed from time to time. While certainly they were better foragers than CX they would have been middle of the pack to the bottom half of foragers in a mixed flock of heritage breed birds. Mine could have been sick or had bad genetics since I got them at TSC and not from a place that specializes in meat birds but that's where I got my Red Rangers too and I found them to be the best free ranging meat birds I ever had.I have noticed the 4 White Broiler chicks I bought do not act super ravenous, they pretty much act like other chickens.
Anyone? There's so many older threads and blog posts about this, there have to be folks with info to share!
https://www.backyardchickens.com/threads/crossing-my-red-ranger-hens.1281099/#post-20657390 this is a thread I had when I was learning about Red Rangers because I happened to get some at TSC. Its not exactly what you are doing, I was crossing Heritage breeds with Red Rangers. All the males were turned into food, and I kept the females alive to see if they could lay. Then I started breeding them to various heritage breeds I had.
https://www.backyardchickens.com/threads/toad-raising.1152440/#post-18045134
This is a guy who crossed a ranger type of bird with CX in an attempt to get CX with larger legs. Its interesting and informative. Its probably one of my favorite threads to read because the guy who started it makes me laugh with his unique sense of humor.
I want to see the results of any project you end up doing with breeding rangers.