We have several paddocks with no shelter, and it has bugged me constantly. In 2021, we lost ~200 lambs in one paddock under the trees when we had constant cold rain and wind for days. The dead lambs were all against the base of the trees, fallen trees and rocks, but still succumbed to the cold and wet conditions. It has bugged me.
We came across some cheap second hand sheets of tin, and some cheap poles. We have started a few experiments in building shelters. In two open paddocks, we are currently building two different best-guess versions of shelter. A photo is below of our first one currently being built.
In the paddock where we lost ~200 lambs to the weather, despite a large tree sheltered area, we are going to build some walls through the trees to provide wind shelter in a few sections - with star pickets and poles with tin sheeting to about 1.5m high. In another paddock that has trees, we will try some strips of shade cloth vertically to see if that is enough to reduce the wind and see if the sheep shelter against it.
I spent some time researching what area we need. I didn't get very far because any calculations were related to a feedlot. We are only building a shelter. Next year we will have mobs of >2,000 sheep. Assuming only 1,000 use the shelter, and they squeeze in at 2 per square metre, we would need 500m2. However, we are going to start with as close to 250m2 as we can get in each of two paddocks and then assess our next steps.
We want to watch if and how the sheep use it. Should we make it deeper (it is currently only 3m deep)? Should be have one long shelter? Or should be have 3-4 shorter shelters in each paddock? Should we put panels inside to reduce bunching up? These are just some of the questions we want to find answers to.
Conditions are still very wet but we have managed to fertilise the pastures to boost them ahead of weaning.