Rushes, rashes, reshes - I think they can be cut and dried for winter bedding, but have a tendency to harbour ticks. The ground could do with being hard grazed before the rushes are cut, then drainage put in. Sheep mostly will only eat them as a very last resort (although someone is bound to say their sheep love them
) You could keep a quiet corner of your field au naturel for wildlife.
We have had three wet years here, each one worse than the one before and I see many previously clean pastures with rushes spreading through them
They eventually end up with more rush than grass.