When you give your chickens greens, do you just give them whole leaves, or do you cut it up? Do you put it in something, or just toss the leaves in? Mine seem to have a little trouble with frond-like greens like carrot tops or fennel fronds... but maybe they just don't like those, or they haven't figured out how to eat them properly. I caught one girl running around with the tail end of a carrot top sticking out of her mouth, the rest down her throat...
Also, do you give them beet greens? I've been looking at this website to see if I should give them things:
http://www.poultryhelp.com/toxicplants.html, and it talks about sugar beet leaves, but doesn't say anything about other beets or chard.