Can You Adopt Older Children Without Vaccinating Them?

A couple with four biological children is interested in adopting through their county's social services program. They have not yet begun their adoption home study. They don't believe in vaccinating their children, who are homeschooled.

What are their chances of having a home study approved?

I do not know the answer to this question, so I thought I'd throw it out into cyberspace to see whether any of my readers have had experiences they'd be willing to share.