I had a recent e-mail from a small farm flock producer in Western Nebraska. Regardless of the time of year, ewes should be shorn prior to lambing. This should be accomplished a minimum of 2 weeks prior to lambing and perferably 3 weeks. One must provide protection from the elements for at least 4-5 days to allow the ewe to acclimate to its new environment without the protection of the wool.
Protection means out of the wind, snow and rain.
Another thing to remember when we take away the insulation, it takes more fuel to keep the house warm. We need to provide some high energy feed, like corn. When feeding corn or other high energy feed, be cautious, start slow and gradually increase and make certain that the dominant matriarch in the peck order doesn't get more than her share. At shearing time you have an excellent opportunity to control external parasites, especially sheep keds and ticks. These parasites cause damage to the wool and pelts plus being an irritation to the ewe.