What are the best settings for taking pictures of dog agility outdoors with a Nikon D7100?

I'm getting some blur using Shutter priority, AF-C 9 point, 1/250, F7-10 range (varies on what camera chooses), ISO 100.

Added (1). Lens was 18-140. I have blur all over the place which I'm not used to as I shoot things liek this often. For example, I have one at F-8, 1/250, ISO 100 56 mm. Then, I have another at F8 1/250, ISO 100, 140 mm. I have the actual settings at ISO-AUTO with 320 F 3.5 set.

Added (2). I should add that I have blur in body. For example, face in focus, blur on legs. Or, oddly focus on body but blur in foreground of grass. I'm used to bokeh when shooting posed pictures but this is unlike that. There was some wind, so many that contributed but I have never seen blur of grass this badly before.

Crank up your ISO to 400 at least, which will allow you to then go to 1/1000sec shutter speed. That should take care of most of your blur. If you find you are still having blur, crank the ISO up even more with even faster shutter speed.

You may also need to set your AF focusing to spot - single point so you can ensure the focus is on the intended subject. This will prevent the camera from focusing on something else and prevent out-of-focus of your dogs due to lack of Depth of Field. Otherwise, it is hard to tell if f/7~10 is sufficient or not as you did not specify your lens focal length.