WATCH: Inside the decade-long fight to free thousands of dogs from testing site

The story behind the beagles that went viral on social media and why activists say hundreds more still need to be saved.

​The story behind the beagles that went viral on social media and why activists say hundreds more still need to be saved.  Nightline The story behind the beagles that went viral on social media and why activists say hundreds more still need to be saved.