We ran a mixed bag of dogs today, and tried something new..
With the cart we ran 5 dogs ~10 miles then after quick breather for baited water we added 3 dogs to this string for a total of 8 dogs and ran ~5 more miles.
This added speed to the end of the run and no one was over worked. the 5 that went 15 miles were in good shape.. overall the SH's were panting a bit as noted by Shelly, The Seppala's were not panting at all at the finish of the 15 miles.