OVER the past 20 years sheep numbers in the North-West of Western Australia have suffered a marked decline. In the Pilbara area, six stations have been abandoned, and about a dozen more are in a precarious position. If these were to be abandoned also, some 10,000,000 acres of sheep country would be idle. It is now known that the shrinking flocks have been caused by a deterioration in the pasture vegetation, particularly the disappearance of the more nutritious native grasses on which breeding ewes depended to provide the high-protein diet required for the production and rearing of their lambs