I'm already finding that - when our other Bovans was killed by the raccoon, they convinced me that I couldn't just replace Buttercup with one chicken; I have to get 2 chickens so we have a backup!
I currently have 3 chickens - an approx. 18-month-old Bovans Brown called Lulu (used to have 2 until we had a racoon visit...), plus a 12-week-old EE called Jellybean and a 12-week-old barred rock called Pepper that I added earlier this spring. Lulu is not super impressed with the new additions...