Stressy Cairn Terrier ... advice please

[Carlosmum]

We have a 9 YO cairn bitch who has lived with us for 3 yrs. She is a very stressy dog by nature but had become much calmer after the loss of her older cairn friend who was rescued with her. For the last 4 weeks my MIL's 10/11 yo bitch (also a rescue cairn) has been staying with us as she (MIL), has been unwell. Everything was fine for the first couple of weeks as Lady (ours) assumed Heather was just visiting but as time has gone on, Heather has only to look at Lady in the wrong way for Lady to start growling/ whining/ followed by barking, not aggressively but defensively. As much as we can, we keep them apart but we have had the occasional scrap & if we are not quick enough my lurcher piles in too.
I know that Lady is only defending her territory but what can we do to help. Sadly we know little about either dog's past lives so we have nothing to work on there.

We have crates in the kitchen but in the evening when we are sitting in front of the TV it would be nice if all the dogs could join us. Should we just accept the problem & keep them separated at all times? Individually both are quite happy with my lurcher.

I expect that Heather will be with us until Christmas and again next Easter as MIL is due to go into hospital again.

 

[Dobiegirl]

It would be wonderful if all dogs got on but like us there are some people/dogs we/they just dont like, what I would do in this situation is not allow the dog to start growling/barking. The minute they opened their mouths I would say quiet and if they started again I would send them out the room, I know this is not going to make them best friends but nothing will but it shows the dog you are in charge, if they cant behave then out the room they go. I would never leave them alone and dont allow toys on the floor for them to pick up as this is a source of conflict.

I have foster dogs and they are here for however long it takes, Im sure my dogs dont like every dog that walks through the door but they have to co-exist in harmony, Im in charge and they know it.