Hi BIB,
Puppy bitches can definitely come in heat at 6 months.
UTI's and vaginitis can make a bitch smell "different" and cause a male to be very interested even if she's not coming in season.
Usually you would see swelling of the vulva before you saw blood.
HOWEVER, puppy bitches sometimes have what is referred to as a "silent season"--no swelling and no bleeding but males will be very interested never the less. Sometime the only way you know that a puppy bitch came in season the first time (if they have a so called "silent season") is because they will subsequently go through an obvious false pregnancy.
Isn't Rommel intact? Just to be on the safe side I'd separate them.