We find our dilemma is that our pasture can hold far more sheep in the summer than the winter (duh!).
We currently have 12 adults and 10 lambs, and the grass is getting away from us big time, such that I'd say we probably need 2-3 times the number of mouths to keep it down.
The problem is, that number would be utterly unworkable in the winter and the place would just turn into a quagmire.
Since this is also relevant to the O/P, can I ask what others do to manage this sort of seasonality? It's playing on my mind at the moment, as 5 acres is taking a loooong time to top with a push mower!
Most would bale the excess for use in winter. I was reading about a guy the other day who bales paddocks and leaves the bales there (small) in little shelters so in the winter he still rotates but doesn't have to bring a machine out everyday and mess the gateways up, the bales are already in place. Difficult balance I would assume.