I have 6 8 week old black sex links they are about half the size of a full grown chicken are the safe to get left out with my adult hens and free range my only concern for predators is our 3 barn cats. They don’t bother the big hens just wondering if they are big enough for the cats to not mess with them
When you free range it's a risk you take and you will eventually loose a bird/birds. Lessons learned the hard way. For years I had no issues and then my birds were discovered. Now they have nice large pens. Good luck...