@gtaus has a lot of good posts about composting in a chicken run.thanks for the idea of putting a compost pile in the run. We've been wanting to start one but haven't gotten around to sitting down and figuring out where to start.
Here's one of his threads:
https://www.backyardchickens.com/threads/harvesting-my-chicken-run-compost-black-gold.1529564/
It works fine for some people.Composting in the run can be problematic, they'll have fun but you may not get any compost....and it can draw preds if you're composting kitchen scraps.
As far as attracting predators, I don't think kitchen scraps make much difference, if the chickens eat all the best kitchen scraps (things like meat) in a timely fashion. Things like carrot peels and cabbage leaves may get eaten or not, but won't be especially attractive to predators either.