5 cases chickenpox @ 7 mo. Baby's daycare. Should we yank from daycare until the incubation period ends so she doesn't keep getting exposed?

Probably too late. The difficult thing about controlling chickenpox is its contageous period. Kids are often most contagious 1-2 days before they break out & may have no other symptoms. You may get lucky & avoid it, but 10-21 days after first true exposure your infant may or may not develop the illness.