My crew loves to poop right at the door.I solved this problem by getting a
piece of plexiglass & making a door just the right size to step over while
keeping the ferts in.
 
Lowes,Home Depot, sell shetts of plexiglass,pretty inexpensive.Get some
hinges,screen door latches,1x2 boards,4 of those if a wide door.
 
Cut your plexiglass & then make the frame to make it sturdy.Mine love to
look at at the twins who are on the other side cooing at the ferts.
 
Hope this helps some.
[Posted in FML issue 3683]