Measure the distance across the front of the run-in shelter. Purchase a length of plastic gutter to fit the shelter, according to the measurement taken.
Make a hole every 12 inches down one side on the top rim of the gutter with a drill. These will be holes for nailing in the gutters.
Set a ladder up in front of the shed. Place the section of gutter on the front of the shed, directly below the roof overhang. Use nails and a hammer to attach the gutter to the shed, nailing through the pre-made holes in the gutter.
Snap a gutter end cap on one end of the gutter section. Snap a downspout onto the other end with a gutter joint. This will direct the runoff from the roof down and away from the shed.
Use a flat-bladed shovel to scoop out the top layer of mud inside and around the shed. Dispose of it in a location away from the shed.
Place a 6-inch layer of crushed gravel on top of the area where you removed the mud. Use a hand tamper to pack down the gravel and create a level surface. The gravel helps with water drainage and will prevent water from pooling inside and around the shed.
Spread a 1-inch layer of fill dirt on top of the gravel layer. This will make the gravel comfortable for the animals.
Spread a layer of wood shavings inside the shed. Rake the shavings around, adding enough to form a 6-inch layer. The wood chips will provide a layer of cushioning for the animals that use the shed and will soak up urine and excess water.
Use a manure fork to clean out animal dung from the shed at least twice weekly. This will prevent mud from forming on top of the wood shavings.