Anybody have ideas
I have little kids who empty out my bookshelves no matter how tight I make the books.
Why are you hogging all the shelf space? You gotta share. Two bottom shelves are for the kids' toys and books. This will probably make the bookshelves top heavy, so they really need to be firmly anchored to the wall.
Buy a big box to store your own books in. Call it Toy Box. As they get a little older, you should be able to convince the kids to trade.