They are omnivores. If a foraging chicken comes on a goat carcass, they may eat some. They eat mice and frogs whenever they catch one. Frequently, chickens will become cannibals. So animal protein has always been an important part of any omnivores' diet. I'm feeding the carcass from our turkey dinner to the chickens today. I grill trapped raccoons and feed them back to the chickens.
I think the key is, moderation in all things. I think Pakistanis understand that philosophy.
I might add that parasitic worms can be picked up by chickens in a variety of insects and other bugs, including snails, slugs, worms, etc.. Those things are secondary hosts to parasitic worms.
That won't affect your meat birds because they won't live that long but it may be an issue with your egg layers.
Your Egyptian Fayoumis are an excellent choice because of their hardiness. They'll need separate housing from your meat birds.