Divider worked well, except I still have air circulation concerns.
Was hard to get humidity up, had to add sponges.
Chicks stayed where they hatched, divider walls are softish and movable, but the shape of the lid in conjunction with the top of wall being very close to lid kept them from being pushed too far.
Will make pattern soon, things are crazy here with spring chores.
What do you think can or should be done to address your air circulation concerns? I'm getting ready to set up my incubator and was planning to order some 7 mesh.