While tomatoes are safe for your chicken’s consumption while red and juicy, their unripe state contains the compound solanine which is harmful. It’s also important to be mindful that both the leaves and stems of tomatoes are part of the nightshade family and contain the same poisonous substance. Oct 21, 2020

An incomplete list of plants that are poisonous to chickens includes daffodils, foxglove, morning glory, yew, jimson weed, tulips, lily of the valley, azaleas, rhododendron, mountain laurel, monkshood, amaryllis, castor bean, trumpet vine, nightshade, nicotiana, and tansy.