Sources, please?
Howabout if they were just "swingers"?
Here's an article that just gives a sampling of the problem:
http://www.rickross.com/reference/polygamy/polygamy69.html
Every time I hear about one of these polygamists on TV, I find myself asking "How does this guy support all of those wives and children?" Then they usually answer the question: He doesn't. The taxpayer does.