New to chickens and had a breach in my yard and lost 3 of my 8 week old chickens today. My kids are very distraught over this and I promised we get more chickens to replace. Before I just put all kept all the chicks in a box for about 6 weeks and then put them in the coop. How do I add new chickens to the coop can I just add the new ones when they are 6-8 weeks as well. What is the common procedure for this.