I have two cocker litter sisters and after I had got them I was advised that I shouldn't have got two bitches together
but by then it was too late and so I was determined that it would work.
It was very difficult house training them as I didn't know who had done what
and whilst I was cleaning up after one, the other would either go too or walk in the puddle
.
They are now nearly 3 and they do have their 'tiffs' but I have learnt to deal with them.
At first, when they argued I would try to separate them, put the one who started it away, treat them as I would children. I quickly learnt this doesn't work.
When they do argue, it is usually over my attention, so I now just walk away and the argument stops.
There is a lot of noise but they have never drawn blood or hurt each other.
Stevie is the more dominant and doesn't like Marley having a cuddle with me so I may sure Marley has her cuddles when Stevie is elsewhere.
Ninety five per cent of the time they are fantastic with each other and are the best of friends.
I know there are other COLers who have siblings who may advise you too.
Good luck