I always worm ewes who have delivered before they go out to pasture. Just check on the wormer data sheet or with your veterinarian that the wormer you are giving gets into the milk or not, and, if so, that this will do no harm to the lamb
If the ewes need to be wormed, go ahead and worm them, it will not hurt the lambs. But do not worm them if
they don't need it, Believe it or not lambs will sometimes nibble on momma's droppings when they first start to
learn to eat solid foods, so if momma is wormy then babies will pick the worms up by nibbling on momma droppings.
Most babies will need to have their first worming at or around 8 weeks old, and then check their eye's and watch
for other signs of parasite infection after that and only worm when nessasary.