Alternate your fields as often as possible _ - Try to make sure about 1/3 of your land each year sees no sheep for 6 months - best time is winter, so graze your wetest fields bald in Oct, leave empty till regrowth in april - 6 months of cold on short grass kills. Generally rotate strictly and choose ewes for worm resitance (I 've already spoken to TIm about buying in Rams for this very trait).
The clean grazing would be best used in a mob stock - Put ALL your sheep on it, tight grazed for a short time, maybe use electric to cut it up into small blocks - meaning they are not re-ingesting their own eggs, then leave the ground and next year cut it.
No need to use wormers unless you have a problem your dealing with - IMO routine worming just hides poor performer that need to be removed from the flock - resistance to worms is the answer,.