I went back through the blog and my calendar and thought about when Chimera's sudden leash reactivity to other dogs started. Last Monday, 11/12, he was at the vet's and saw other dogs while on leash, and was curious but calm. On Wednesday 11/14, we went to the Berkeley Marina and he met a couple of dogs off leash and was well-behaved. At the end of our trip we passed by a terrier who was reactive and surprised Cai by charging and barking. I remember that Cai got a little scared. On Thursday the 15th, I first saw reactivity. I picked him up so that we could pass by a big dog without Cai rudely jumping on him, and when the dog leaned in and up to try to get a sniff, Cai gave a short growl and a couple of defensive barks. On our way back to the car, back on leash, a couple of large dogs were coming toward us from behind. Cai noticed them when they were roughly 50 feet behind us, and started growling and barking. Since then he's had off leash time with other dogs (mostly fellow small dogs) and acted normally, but has been growling and barking at even the sound of dog tags jingling. It really was a change overnight. I assume that the terrier scaring him and the confinement of being held/on leash was what triggered a general change. He had always been worried when he heard dogs being reactive or alarm barking -- he would lower his tail and his eyes would get wide, and he would stop and stare. But until this started, I had been able to talk him through it and get him moving again with treats.
This morning the rain was still coming down, so I drove to Home Depot and we took a "walk" through the store. We stopped frequently for mini training sessions -- circle work and heeling, sit in front, down, agility sends to a treat (putting my on-side leg and arm forward and tossing a treat ahead of us), putting his front paws onto a few objects. His focus was impressive among all the distractions, but of course the sessions were super short, 5 reps or less.
He went into his crate for his afternoon nap. When I got home, instead of taking a shower and then letting him out to potty, which leads to him barking for ten minutes or so, I went straight to my room before he was even fully awake and took him outside. I let him play with Jasper for five minutes, and then I put him back into the crate with an ice cube of chicken broth. Alas, it didn't last quite long enough, and he started barking again as I was finishing my shower. Again I tried something different: instead of waiting him out to reward being quiet, I interrupted his barking and told him to sit. He did, and from there I was able to give a number of treats for being quiet, and he didn't get as worked up as he usually does.
My roommate's eight year old daughter was visiting and Chimera played with her quite a bit. We practiced many different tricks. He was slowing down by 7 pm, and was super tired by 8, and I couldn't keep him awake any longer. After a 45 minute nap, I was able to get him up and playing and then chewing on a new bone, to keep him from sleeping too much too early.