How old does a chicken have to be before it is considered full grown. I have a hen that is really small but she is about 7 months old. Is she done growing? Also, I want to get some silkies this spring and they only come strait run. My cock to hen ratio is at it's limit. Will it be okay if I end up with another roo or 2. Silkies seem more docile. Will they settle into the natural pecking order or will I have fighting. Thanks for any help.