As for feeding eggs to chickens, eggs are a great source of protein, but IMHO should be fed only when cooked and mashed up, so the girls dont get the idea that eggs = food. Chickens are very suggestible, and if they think eggs are good to eat, they wont wait for you to cook them!
When I get an egg that has been pecked, I hard-boil it, mash it up, and feed it back to my girls. They fight over every scrap. Scary, but true. Friends of mine toss their old eggs into the woods -- why waste the protein and encourage varmints to come closer to the coop?
As for feeding meat to chickens, they're omnivores, so they'll eat meat if they can get it. I've heard that they like mice. Wish mine would eat the mice that hole up in the coop! I'm sure chickens would eat a snake, too, if the snake was small enough. And as you know, there's lots of meat on a cricket's legs. Chickens wont lay eggs without sufficient protein, and I dont think they care about the source.