As ewes get closer to lambing, they get larger and more vulnerable. Ensure you have enough trough space. There should be 60cm (2ft) for big ewes (80kg+) (Suffolk and Texel cross, etc) and 45cm (1.5ft) for medium-sized ewes (70-75kg).
Keep an eye on ewe body condition. If ewes are losing condition, you need to increase feeding levels. Ensuring that ewes lamb down in good body condition improves lamb survival rates. Do a shopping list of items you need to purchase before lambing starts.