When you are worried for the health of your chickens, it's natural to want to give them something that you hope will make them better. But the consequences may not be what you wanted and hoped for. This article casts parasites in a new and more interesting light.
https://grist.org/video/parasite-climate-change-ecosystem-health-science/
https://grist.org/video/parasite-climate-change-ecosystem-health-science/