So you are saying you can get 3 week old or 7 week old chicks if one dies at that age? Mine usually need that companion until thy mature enough to join the pecking order, usually about the time they start to lay. If you get an older second chick you have two integrations, the two chicks to each other as well as to the older flock.My plan was to run out and grab another if a chick dies.
Excellent idea, that's what I do. This kind of implies you have a decent size coop, not sure about your run. Mine roam with the adults at five weeks but I have plenty of room, a large coop and two shelters where they could sleep, over 3,000 square feet outside, and weather that the outside is available practically every day. I think room has a lot to do with this, that's why others are asking. Of course there are exceptions, there always are, but mine tend to form a sub-flock and avoid the adults until they mature. This includes chicks raised by a broody hen, not just my brooder chicks. From the time a broody hen weans them until they mature enough to join the flock they usually form a sub-flock.I was going to brood them in the coop to help with integration.
Two provide comfort to each other if the adults don't allow them to stay with the main flock. You can manage to integrate just one but that can sometimes be harder. A lot of that can depend on the individual personalities of the chickens involved. Sometimes that is not a big deal. You never know how it will work out. It's unlikely any will die, especially if you get them past the first week or two. If you lose one you can still manage just one. It might or might not be harder, people integrate one all the time.
My personal preference is a minimum of three to greatly reduce the possibility I'd have to work that hard. This is a personal preference, not an absolute law of nature. If you really don't want more than two you can try and it will probably work.