Here is a reply I got back from Discovery

I hear you loud and clear Heartland Thunder fans. I, too, loved the show and was sad to learn that it would not finish out its run on Discovery Channel. But because of your loyalty to the show, the network has agreed to put the remaining episodes online – in full! That's right; you can watch the entire series online starting Friday, July 23.

Here is the schedule of when each episode will air online:
Episodes 1 and 2 will be online as of Friday 7/23
Episode 3 will be online as of Tuesday 7/27
Episode 4 will be online as of Wednesday 7/28
Episode 5 will be online as of Thursday 7/29
Episode 6 will be online as of Friday 7/30

you can either go to the site and put heartland thunder in the search or try this link

http://dsc.discovery.com/search/resu...rtland+thunder