There are so many bird illnesses, I almost decided to vaccinate. But, my flock has remained healthy without them, and personally I know of several more organic flocks that have never had issues other than mites/lice. Out of curiosity, which illnesses continue to be a danger in adulthood? Do all chickens carry Salmonella, and is there a way to find out if they have it? How does it get introduced? The main issue that they've all had to deal with is insect infestation. Is the best way to prevent it hygiene and diatoms and cayenne pepper? Anything else? What should I keep on hand in case they DO get fleas, mites or lice?