We have an 8 year old greyhound. We have just had a 12 week old border collie. Did lots of reading around introductions but it was tricky as it was late evening so couldn’t take them somewhere neutral. We are on day 3 now and our greyhound just keeps barking at the pup! I know I have to allow them to sort this out (there is no sign of attack!) but the barking is constant when the pup is moving around until we make the greyhound lie down on his bed. When he’s asleep the greyhound is settled. Any ideas?