I give everything a good clean and spray with fam30 before lambing, inc hurdles and floors, leave to dry. Then hydrated lime and lots of straw. I don’t have time to use fam inbetween occupants during lambing, so clean out and sweep out pens and more lime and straw. Straw pens every morning, try not to leave ewes and lambs in individual pens for longer than they need to be.