Zylina Healthy Mealworm Chicken Supplement with Probiotic Additive features a plant-based probiotic that supports your flock’s digestive health when used daily. Not only are these mealworms a tasty and nutritious treat, but they are also rich in protein and great for molting support. And with the added BOOST. Probiotic, your hens can experience improved feather growth, stronger eggshells, and an enhanced immune system.