Thanks for this question Kevin.
There can be a lot of positives in getting a second dog. It can provide company and a play mate to your current dog. However, getting another dog with the hope of it teaching your current dog good behaviour is very high risk. I say this for the following reasons: –
1. You don’t know how the new dog will settle into your new home
2. You don’t know how the new dog will take to your current dog (or vice versa)
3. You don’t know how the new dog will behave once it has settled
4. Even if you get a calm dog you don’t know how it’s energy will fluctuate in different circumstances and situations (i.e other dog, people, guests, bikes etc)
5. The new dog may learn from your dog and you may have to ill-behaved dogs to contend with
My recommendation would be not to consider 2nd dog until you have managed to obtain the desired behaviour from your current dog. By using the 5 Cs (see my previous post on this) combined with plenty of games and mental stimulation then this will be the best route to success. I would prefer that your dog learn from you rather than rely on the unknown factor of a new dog.
I hope this helps