You do not have to wait until they are the same size to integrate. Once they've seen each other between the fence for a couple of weeks, let them all free range together.Thank you! I love my feathered friends and look forward to learning the new ones personalities! We let our older chicks free range and look forward to putting the new babies in with them eventually. We have 4 new ducklings that also free range with the older chicks with no problems since we introduced them. The new chicks, Lucy & Ethel are still too small to free range with the others but we put them outside in a separate run during the day so they can get used to each other thru the safety of the run. Once they're the same size I'm told it's safe to put them all together but I worry about my lead chick. She already chest butts the fence so will she be aggressive towards them when I don't have the fence protecting them? Any advice?
When you write 'free range' that means no fences. If there are fences stopping their movement, they are penned. Lots and lots of space and places to hide and perch on are keys to a successful, rather uneventful integration.