I found this fun little invention for child protection called the Kiddie Koop. It is basically the same concept as a chicken coop, or a playpen on stilts that is completely enclosed.
The Kiddie Koop was patented in Nov 25, 1913 by Edward Maurice Trimble of Rochester, New York. It is basically supposed to be a combination Crib and Play Pen.
According to the Patent Application, the crib could be lowered to the floor and the top removed so the baby could play.
To be used as a crib, the legs can be raised and covered so it can be an enclosed crib.
Sounds really interesting, because it could be folded up like a carrying crib of today.
Wonder why it fell out of style. All I can think of is that not many kids wanted to feel like a chicken in a cage.