Thank you for providing an excellent, fact filled article. Even people with healthy immune systems should practice your advice of wearing a mask and practicing bio security in their coop. I developed organic toxic dust syndrome a number of years ago after going to work in what was considered a high bio security hog concern. I'd worked in hog barns for years and never had a problem but it put me down fast and ended my time in the barns. I didn't think about the chickens causing me any problems but within 2 weeks I was having severe pain in my legs and back, wanted to go to sleep by 6pm and just felt bla. My husband finally told me to use my nebulizer and do a lung treatment and start wearing a mask around the chickens. Bingo, leg and back pain gone. I'm still tired but that will pass in a few days. I have a number of auto immune issues and a rare disease I have to watch closely that I've probably flared. Diseases from barns or coops are nothing to mess with. The authors recommendations to wear a mask, have designated clothing and shoes for the coop should be mandatory for anyone entering your coop. Bio security is vital for both your health and the health of your flock. Thank you again for such an important and well written article.