Definitely check your ground rods. I had trouble with bad grounding this summer and it wasn't shocking horses (I also had numerous people touch the fence when it was hot and they got no shock so I investigated further and the ground was like dust, bad ground). If you are like most of the country the dirt is just too dry to create a sufficient ground. It also helps if you have more than just one ground rod, preferably 3, placed in a triangle 10' apart, connected to each other with copper wire. And as already noted, if you thoroughly soak the rods it will make things much better. Whenever I would fill the water tank, about 1-2 times a week, I would let the hose run on the ground rods to soak the area, didn't have a problem after that. And you can buy a fence tester so you don't have to touch the fence yourself lol but yeah, if you don't have one, touch it and make sure you get zapped.