Please help,

My pups are turning 1 next week and up to now everything has gone really well.

Tilly has started attacking her brother very aggressively. We thought it started as resource guarding so took all bones and toys away.  But now it happens for seemingly no reason.  She starts to growl so Alfie turns his head away, no eye contact and wont move.  He doesnt respond and then BAM, shes on him.

We wheelbarrow her away and shut her in the crate but still she barks and Alfie wont move still, or walk past her crate. We have to carry him away.

She had her first season in February.

After 15, 20 mins she is all calm again. Snuggled up with her brother.

They do eat separately, I watch them and remove bowls immeadiately.

She is a lovely girl but I am getting very worried about this aggression now as she cant tell who or what she is savaging once she starts.

Thank you for any idea's.

Angie

What breed and why did you keep two? Sibling rivalry/competition but could also be breed linked. Can you tell us more please?

Phantom Pregnancy could be at work here also.

Did the behaviour start after her season or has it always been a feature of their relationship?  Did you get Alfie neutered in December as you had planned?

Alfie sounds as if he is managing himself quite well.  I have regular visits from the sisters of both of my younger dogs and the girls have always been very bossy with their brothers.  The sister of my youngest boy pushes him the ground, bangs his head on the floor and pummels his chest (he genuinely doesn't seem to mind).  He also has a lovely way of standing still, averting his head and looking the ceiling when his sister and his mother take a turn at encouraging him to engage or even if my other entire male gets a bit pushy with him :)  Is Alfie frightened, has she drawn blood, or it is all noise?  Is there a time of day when this behaviour is more likely?

I don't understand the term wheelbarrow - does this mean you are dragging her away?  Is this the only way you can manage it or does she respond to a command?  I think a bit more information about her timings and your responses might be useful

Now if you had said they were both bitches I would not have been that surprised but I am surprised if she is turning on a male. Competition between bitches is fairly common and can be so bad that the only answer is to re-home one of them but as this is a male she is attacking I would have her checked over by the vet to make sure she is well and not having a phantom. The only answer may be to spay her but that depends on the breed as if it is a large breed it is too soon to do that.

I see it is possible you have already castrated the male and if that is so it could be the answer to the problem, castrated males can smell to other dogs like a bitch in season and if this is so it would explain her behaviour.