Legal Question in Employment Law in California

It is up to the discretion of the employer how they wish to communicate work schedules. There is no law that addresses this. Of course, a well managed employer will announce work schedules as far in advance as is practical, depending on the type of business it is, so employees can plan accordingly. This makes for a happier, more productive workforce. But it is not illegal for a company to be poorly managed. It just results in higher employee turnover.