Butter wouldn't melt

They have both been very good today, completely different from last night's after work walk.
While walking through one of my local woods a deer suddenly ran across the path about a metre behind me, the dogs were obviously alerted to it and Jess took off, I tried to grab her harness as she went by but she was moving too fast, Dina didn't want to miss out and off she went after Jess.
Now Jess hasn't chased a deer for over a year now, I assumed she realised her disabilities, and this has lulled me into a false sense of security and I no longer routinely put her tracker on.
Dina on the other hand always wears her tracker as smells can overwhelm her hearing!? and I like to see where she is.
I spent a worrying few minutes calling and whistling slowly making my way towards where Dina was in the hope they were both still together, Jess suddenly comes running up to me with a huge grin on her face, we had to wait a few more minutes while I watched Dina's track on my phone start to go back up the trail I had just come down, she obviously realised the scent was getting older and turned around and found me. Today they both had their trackers on