Sorry, I said quarantine meaning isolation for a sick bird. And although I agree with you, I am certainly not an expert, and when we got our first illness and looked up on what to do isolation was often the first advice given on chicken blogs by people who make a living out of it. Put the chicken in a small box or cage on its own and cover it in the dark so it can rest.You may have skimmed my post like I said, because chickens hide sickness by the time we notice a sick bird, if it has something contagious then it may have already spread. And if the others are fine, then it's not contagious. Either way, leave sick birds with their friends.
I had Mr. Bumble inside so I could more easily keep an eye on him. Plus it was convenient to just be able to scoop him up right there to feed him.
I agree isolation does make sense when you have to closely monitor what a chicken eats or drinks. I have noticed they can sometimes pretend to eat and not actually eat anything, which is difficult to see when they are with the flock. I also agree it's necessary if you need to protect them from the rest of the flock.