I think they like the veggies after they've sat in the water a little bit if they're raw or cooked. I'm not a crayfish expert, although I think it would be cool to own one.. I'll move this thread over to the forum and see if you get more responses from the other crayfish owners who will know better than me.
Your cray won't likely care, unless he/she is being finky or just a pain in the booty, like mine is doing. She won't eat most anything right now. Which means...she's either mad about being moved to the 20 gallon tank from the 55, or she's getting ready to moult.