This might be a silly question, but... Everyone talks about how good black oil sunflower seeds are for chickens, do you give them the seeds with the shells on? Aren't the shells too tough for them? I just picture those hard scratchy shells scraping the chickens soft fleshy crop! I experienced an impacted crop once and do not want to jeopardize another one! Maybe it is my own bias because I can't pop 'em in my mouth and split them open with my teeth! My dad is a pro and can spit out the clean shells... I'm jealous!