Shifts (being groups of workers that start and finish at a particular time en masse) themselves are probably contrary to good practice wrt patient care. If the whole shift changes then it seems there would be a substantial discontinuity in care; you'd want people to have staggered work patterns so in any hour there is always a substantial proportion of staff who were there the previous hour.

Unless you have many-to-one carers-to-patients then it wouldn't matter so much.