fence jumping is a serious thing my Bindi could do a 6 foot fence from standing next to it… I have no experience with an invisible fence but no doubt a husky with strong will power to run will ignore it totally...
a mile a day is is nothing what so ever there were times, and i think a lot of owners will say the same, when i used to run mine for 45 mins to an hour after 30 mins they were up and ready to go again… a treadmill could work out i have not used one myself… mental training can also make them tired, for example hand touch training is something i did...