Dog had a dog-reactive issue with foster mom. Been with me six weeks now, want to introduce to neighbor's dog face-to-face

Question

My dog, a 75-ish pounds 1.5YO male Lab/Boxer/whoknowswhatmix, apparently liked his foster mom's dog, but no other, to the point of seriously injuring her friend's dog apparently. Given that he liked her dog, that seems to indicate to me that maybe it's not a dog issue as much as situational and/or person-reading.

When she first brought him over here, on leash and gentle leader, he and this particular neighbor dog who's up for a play date barked at each through the fence. Neighbor dog was trying to eat his way through the fence as well. Within about 48 hours, they had transitioned to non-obsessive fence running, casual sniffing, etc. No barks nor growls since that day, no aggression at all, same with the other big dog at another neighbor's place.

His old foster mom is highly concerned, is asking me to rethink this weekend playdate, given her past experiences. Given six weeks of observation of the two dogs, I'm pretty comfortable making the face-to--face introduction. That said, I intend to have them meet on-leash at a neutral spot down the block, see how they do with some walking, before bringing them back to our yard (more room) and considering off-leash.

I respect his foster mom, so her concerns concern me. I'd be interested in the thoughts of others. I've had big, often male, sometimes aggressive, dogs, my entire life. I've dealt with various behavior issues, including aggression, in the past. I'm not naive walking into this, but I don't have her experience either, so again, her concerns do concern me a bit. That said, I think these dogs have been great at the fence, and it would be excellent to let them run around together in a way that doesn't burn paths into the grass so much, and maybe tires them out even more.

Are there additional precautions that I should take before introduction?

Answer 1

Your approach sounds good: take it slowly. Start with no more than 3 seconds of nose-to-nose and separate them. Watch body language for both dogs as they meet. Walk them past each other at first, then you can try going in the same direction if things go well.

I would suggest that if you get to the point where you want them to meet off-leash, that you leave the leashes on and let them drag them. That will make it easier to catch and separate them if things start to go badly. But the main point is to progress slowly and cautiously, being prepared to separate them at all times. I would spread this over a number of days if either dogs is showing any signs of stiffness or hesitation.