Full episodes of "Heartland" season four are available through the "Heartland" page on CBC.CA, as of 2015. The show is also available for purchase through iTunes and Amazon.com.
To view episodes on CBC.CA, visit the site's home page and click TV. Click Shows, and click "Heartland" on the Shows page. On the "Heartland" page, click Episodes, and then click on 4 under the Choose A Season heading. Click on the title or icon next to an episode to view its episode page. Each episode page includes the episode video, a summary of the episode and a cast list for that episode.
To purchase the show on iTunes or Amazon.com, perform a search for "Heartland Season 4" on either service. Amazon.com has the season four DVD available while iTunes offers downloads of the entire season and individual episodes.