Hill sheep production systems are extremely important in the UK. They are the dominant land use in areas of important landscapes and tourism and sheep have major influences on habitats of nature conservation value. There is considerable debate about management to achieve nature conservation objectives. This debate tends to centre on overall reductions in stocking densities. However, other factors influence the impact of sheep on semi-natural pastures. An experiment is described that shows that sheep fed compounded pellets daily show different grazing and social behaviour compared to sheep offered ad libitum feedblocks.