Well, mad cow disease showed us that if you feed an animal that same animal, or even when humans ate humans (i.e. studies done by cannibalistic tribes in Papau New Guinea), you get horrible neurological breakdowns over the generations of offspring.
I would not recommend feeding chicken to chickens.
As for the beans and peas, it is only the raw version that is bad for them. Cooked is fine.
I understand but let see if I can get DH to stop tossing bones to the girls. People come in out back yard and think somethingS have been killed back there. At one time they had a whole turkey carcas they had picked clean. Everyone thought it was funny in a creepy way till one of the chickens tried to crawl inside it.
And BBQ ribs.....they eat those all the time. I think today I walked aroudn the yard and filled a bucket with the bones left from the rib scraps they got.