I know a fair amount of care should be taken when introducing young chickens to an established older flock but what about mixing chicks with other chicks? I want to get a few day olds from a local feed store but the breeds I'm interested in come from a couple different stores. So if I was able to pick them all up within the span of a week or two, could I have pretty good success mixing them in the brooder? What concerns should I be looking out for?