We have a 4'x4' foldable dog fence w/ walk-in door we keep for isolating birds. We clip a bird net over the top so a hen doesn't fly out...however we don't use the net w/ Silkies who can't fly/jump that high to escape.A small dog crate is a very good investment. Not just for broody breaking, but for any time you need to keep a bird separate.
It folds flat when you don't need it and takes up very little space.
Our folding fence is similar to this style w/ walk-in door shapeable as an octagon, square or rectangle.
