I've never met these people, so I can't say for sure, but judging from the incredibly anti homeschooling statist slant throughout the rest of the article, I'd guess two or so cats would have been considered a houseful of critters in this particular instance.
...The team that reviewed the circumstances of the murder-suicide last July said Johnston County social workers tried to protect the children but lacked some tools that could help prevent future deaths from child abuse or neglect...
Sounds like that pesky old Second Amendment again.