We have an almost 5 year old cockapoo. He's always been nervous of larger dogs but generally playful and friendly with smaller ones, but over the past year he's become more reactive and snappy with all sizes; not all dogs but it's unpredictable how he'll react when one approaches.
I consulted a behaviourist during lockdown but she wanted me to video the behaviour before she'd come and see him in person (and I didn't really feel comfortable with letting him act like a dick to some poor dog while I just filmed!).
We've now moved and I'd really like to tackle this, but at 5 years old, is the behaviour too ingrained now? Part of the problem is that he gives little warning - rarely growls - but goes straight in to have a pop, so as this is a practiced behaviour presumably it'll be hard to stop it Sadly? Sadly we don't have any local friends with friendly dogs so can't socialise him on a regular basis.