Our dog is almost three and has always barked if somebody comes to the door and when we leave (even if only one of us is leaving and the rest of us are at home- once they've left, she returns to her usual calm state immediately.)
The barking seems to have got worse recently and I need to try to stop it.
She's a collie and intelligent but very stubborn/ resistant to training. If we try too much she will retreat, refuse treats and ignore us.
We got as far as training her to go to 'her' space when anyone comes to the door but she still barks there. She doesn't bark at any other time and is super friendly. Luckily we are rural so no neighbours hear!
If anyone has any creative responses please do share, we are happy to spend as much time and energy on this!