Chickens can pick up worms indirectly through an intermediary host. In this scenario, worm eggs are expelled from an infected bird either through their faeces (hair and tapeworm) or, in the case of gapeworm which is found in the respiratory system, coughed up. At this stage, the worm eggs aren’t infective. Intermediary hosts (earthworms, snails, centipedes and houseflies) will eat the worm eggs. Your chickens then eat the intermediary host, along with the worm eggs that the host has ingested and your hens become infected. The larvae hatch inside your hen and the cycle repeats itself.