Sorry this might be a long one.
Mum passed away suddenly a little short of two weeks ago leaving behind two border collies, a 6 year old boy and 10 year old girl. My brother has been living with her while the purchase of his new house went through and was looking after both dogs when my mum went in for surgery but unfortunately she suffered complications. My brother is due to complete on his house in the next few weeks and can take the younger but can't take them both. I don't have to take her immediately but only have a couple of weeks to try and sort this out.
I'm happy to take the 10 year old, she's a sweetheart and great with kids and dogs. The issue is I have 2 dogs myself. A 13 year old pom who will have no issues whatsoever as he just loves life, and a 6 year old very sweet but very nervy dog reactive border collie. She gets on brilliantly with the pom (in fact he bosses her about a bit) but he was here first and she's always known him.
My dog's reactivity is definitely some fear and a lack of socialisation. She had an op to remove a growth on her leg at 4 months and was on crate rest for ages because it refused to heal. She ended up with a skin graft eventually but it meant she missed her peak socialisation period and has been not great with dogs since.
She can be managed on walks and doesnt lunge or bark if she sees another dog but will try and get away. On lead she'll just try and skitter past them unless the dog comes right up to her. She'll try to back away but will growl and air snap (never bitten but i cant say that she wouldn't, she's just not really had the opportunity). Off lead if she has a ball she will actively run with other dogs and will even let them take the ball with no squabbles. She's been walked with mums dogs pretty often but always with the ball. The one time she didn't have the ball was a few years ago and she did have a spat with the younger dog because he was trying to herd her and wouldn't let her get away. It was a full on lunge at him and she did pull fur out with her teeth but didn't break the skin. Since then I always made sure that I had at least 2 with me.
In the house we've had dogs visit before and she really doesn't like it. She'll growl and pace, bares teeth and is really not happy. Again if we get the ball out we can distract her and she just wants to play but obviously we cant just play with a ball 24 hours a day. We tend to not allow the ball in the house as she is ridiculously obsessed and will just drop it on your lap over and over, even if you dont touch it. We're open plan in the house so no way to separate with stair gates etc to give them their own space and to get them used to each other. My dog is crate trained (I think mum's was too), or was but we put it away ages ago as it was no longer needed. It's in the shed so we can get it back out and get her using it again.
Does anyone have any tips for getting them comfortable together? I don't want to do this wrong.