Onion: A Natural Ally for Healthy Chickens 1 Onion works as a natural antibiotic, helping protect chickens from infections. 2 It clears their lungs and supports easier breathing when they cough or face respiratory issues. 3 It boosts their vitality, giving them more energy and improving appetite. 4 By aiding digestion, it helps chickens absorb nutrients from their feed more effectively. 5 It strengthens their feathers, making the plumage shinier and healthier. Onion is a simple, natural, and chemical-free remedy to keep chickens strong, active, and in better overall health.