Grace......While I can freely admit I am totally baffled by the Duggars non-stop reproduction and the outlandish size of their family, I wouldn't agree to the term, "abuse" with regard to any of their children.
They are not only unique in "size".....but they also stand out from the crowd in numerous other ways.
The Duggars are original husband and wife and all children are their own biological offspring. They are totally self-supporting and receive no assistance whatsoever. All of the children are and have been Home-Schooled and rank amongst their peers who attend schools, as above average to high achievers.
They are public about their Christian Faith, family worship and adherence to the Bible and teach their kids accordingly.
As in most any family with more than 2 or 3 children, the older children will help with the younger kids and often spend time together purely as siblings.
It has not ever appeared that the older children, girls or boys are ever forced to supervise or watch after their younger siblings. It seems only to be a group type of effort. This activity and experience certainly can't hurt them, providing it's not excessive.
These parents are dedicated, hard working and as far as we can tell, very loving people. I can't imagine any "investigation" being necessary or even appropriate.
Having said all this however.....no disrespect intended.....it might not be a bad idea for the parents to have their heads examined!!!!! WHAT the hell are they thinking??? LOL