My crossbreed bitch is on day 14 of her season. I thought ide missed it as she started flagging her tail about 3wks ago so I was surprised when she did start bleeding. Im due to take her to my friend tomorrow for a couple of days. She has an entire male. Is it wise not to take her?, she is quiet in herself but unusually aggressive to my other female dog and my other friends castrated male. Does that mean that she could still get caught?. And why would she flag her tail before her season started?. I'm a bit confused.

I wouldn't advise taking her unless your friend is extremely careful and responsible tbh! Not to mention prepared for both dog and bitch to be very determined to get to each other, and for the dog to start marking in the house to claim his territory.

Thank you for your reply, I thinks it's probably safer to leave her with a family member who doesn't have dogs.

I agree more sensible amd safe to leave her with some one u trust making sure they to understand that any walks will have to be done away from other dogs and on lead .I've always kept my in season bitches away and in lead for a full month  to be absoultley safe.

> And why would she flag her tail before her season started?. I'm a bit confused.

She is a natural slapper? 

Seriously though, I have had bitches flag early on in a season, well before they are "ready" and I have spayed bitches who will flag when I stroke them.  Bitches are not reliable to be honest. 

Should I be watching out for her flagging again or has she gone too long now?

I count 4 weeks from first day of season and don't worry about behaviour changes flagging etc . I don't breed and  my only thought is to keep her safe from any possible pregnancy so all our walks are in lead and away from other dogs expect my own  neutered  male. I don't think it matters when she is or was flagging as you are just trying to prevent pregamcy which is not only going to happen when she is flagging.4 weeks from when she started bleeding should keep her safe

Thanks. That's true that I don't need to watch for signs just keep her safe from other dogs. I think I was over thinking it.

It could be that her season progression hasn't been in the usual order, so to speak.  Willow started last Monday - or so I thought.  I saw blood spots, and that's the typical first sign with her.  On Thursday, she started flagging and Thursday evening, she tied with my brand new (and thankfully neutered) dog!  So she was much further on than I thought.  Ordinarily I can tick off when she's started and when she'l start flagging but not this time.  I honestly haven't got a clue what day she's on except that she's maybe a couple of weeks through.  She was 2.5 months overdue for it too so this time, all vets are off!