Just a thought,
A feed rim and a flat migratory cover.
One side is the feed rim and the other side is for the patties.
The feed rim side has 3/4" plywood on both ends and a 2" wide plywood side for stability.
Just flip the cover for it's intended use.
August -September use the feed rim side down so that it encloses the patties.
Later on when you want to feed between the brood chambers you can flip the cover over and have the flat side down.
Comments are needed.
I will make a prototype to see what problems occur.