I add a few birds every year, trying to keep my flock number below 15. Some adult birds I give away locally, and some die. It is a bit of a balancing act, between keeping an age-variable flock but sticking to the number I can handle in the winter coop. You could easily just add a few new birds every 2-3 years as said above.I have a question, I have 7 chickens that will be a year old in March, at what point do you start bringing in new babies to replace the old to keep an egg supply coming in?