Chickens love greens, seeds, bugs, grubs, and their nutritious feed. Try a can of kitten food or small meat chunks cat food or a few mealworms. They just might be craving some sort of meat source in addition to feed and greens. They love crickets if you catch some overnight in a milk carton or dig up earthworms under a brick. Try a little wild bird seed mix - a good one - not one full of dry coarse ground up corn bits! We give our birds a slice of cantaloupe, cooked brown organic rice (not white rice), add Rooster Booster vitamin supplement to the rice with Brewer's Yeast powder and a little sprinkle of bee pollen seedlets. We give cucumber slices, shelled raw sunflower seeds, watermelon (hot days), corn off the cob, banana pieces, blueberries, cooked shrimp or fish (no bones), cooked turkey bits (no onion salt or onion powder or onions in the cooking), cut up lettuces and chard, etc. Something should grab your Silkies' attention and fuel their appetites. One day they crave one food and the next day something totally different. When we try a new produce to give our Silkies, we break off tiny pieces and hand feed it to them to see if they like it. Usually they love anything you hand-feed them. Ours wouldn't eat banana for 5 years until I offered a tiny piece to a Silkie and she went nuts for it and the other chickens came running to get some too. These are suggestions to add variety to their diet in small amounts but their feed should continue being their main source of nutrition.
Please tell me where you get your bee pollen seedless, and shelled raw sunflower seeds (I am assuming you are not removing the shells yourself). I would like to get some.