How do you define ‘sick?’ Every living being is constantly under assault by environment, other organisms and even itself (cancer, autoimmune…). The immune system and cellular growth can fix or minimize some of these issues, but disease and death is inevitable for every living thing. You have no doubt had a cold, your houseplants have died mysteriously, your cat drags in a dead mouse (whether he killed it or not!)…. If you mean catastrophic flock disasters like bird flu, then no, happily most flocks go forward without losing 90% of their birds in 3 days. But every flock has sporadic outbreaks of coccidia or mites or a deformed chick or a fox or an egg bound hen or mareks or whatever, it doesn’t mean you are doing something wrong only that you have living organisms around. You only see so much death and destruction here because people are asking for help in the midst of crisis, you rarely hear anything when things are going well. Just like cancer rates skyrocket when we develop a test for a certain type, the actual cancer rates are the same, it is only our ability to detect them that has changed and thus our perception. Just like everyone now dies of heart disease, cancer or diabetes in their 70s+ while a hundred years ago it was infectious disease and accident while making it to 50+ was a great accomplishment. Modern medicine and better living/working conditions have eradicated most of those old school mortality factors allowing us to die of other stuff instead, our bodies basically wear out: organ failure or cancer, whereas most people didn’t live long enough back then to wear out, the rates were significantly lower both because of shorter lifespans and nobody was diagnosing or recording cancer rates and heart disease back then (at least on a population level). Life is dangerous, nobody gets out alive, so you should probably enjoy the journey! To which our animal friends can contribute significantly, even if they add their own stress and sorrow but that is the price of love and life too!