A good speed for a hound in a big fox pen. Will be 9 to 11mph. If you really know how to run your GPS. You can pick out your front line from your pack dogs. But every thing comes in to play.
On my alpha my dogs run at least 3 miles an average faster than they did on my 320. I always wondered why my buddy dogs average faster than mine and they were running side by side most of the day now I know why the Alpha picked up different than the 320.
On the outside, in the thick brush on gray fox, where I hunt, 6-7 mph average is a good speed. Sometimes the hound that keeps getting thrown out and spends a lot of time trying to get back in the race (using the road and such) will cover more distance at a higher average speed than the hounds actually running the fox.
As said above, all depends on terrain, if hound is running game down a path, open woods, pasture compared to palmettos, scrub, briers and vines.
Come to Old 74 and run 9-11 MPH and you will win every hunt! LOL unless its in the Road. Watch your hounds and a lot of the time your slowest hound per Garmin will be running the most game. Just an Old Fat Mans opinion.