I started with well-worn ISAs, who layed for a while and then went into retirement. Only have two old girls left, plus a motley crew of 5 youngish mixed breed EE/mop-heads, who produce three eggs a day between them. I'd like to get some good old RRs, and could split my chicken run to keep newbies and older ones separate. I'm afraid to try really young birds but wonder if it's possible to get some that are about 3-6 months old and also can one tell their sex by then? I don't want roosters and don't want to kill them either if they are males. I can place a want ad in the local used.com site but I'm not sure what to ask for. Any advice?