Can my red eared slider eat crayfish/crawdads?

I have a pet red eared slider. I just began starting to feed him live food. I have fed him red rosy minnows and comet goldfish along with some live crickets. I was wondering if it's safe to feed him crayfish. I have fed him about two and he has eaten them I just wanted to make sure they are safe and if so what is the maximum length I should feed him? One last thing when I have fed him in the past I cut off the claws if they are big so he doesn't get pinched.