I just had an employee call in sick and I was thinking of the all the things which could be added within this moment.
-Adding a role of store manager-
This employee would obviously have a hire salary than a standard employee and would fill in, in the case of a sick employee. At least here in the US, it is rather common unfortunately for them, for a store manager to work 60-80 hours depending on the business. You would have to establish a cap of hours, at least for my idea but, if the manager hit their cap, you would then get a notification. This would present an option to have an employee stay late for overtime. Call someone in early for overtime, close the store at the end of their shift, or you fill in. For the employee assigned at 0000, you may have to close the store until you arrive.
-Introduce vacation days-
A family member of mine gets four weeks every year of vacation. They can use that anytime and all they have to do is contact their first line supervisor/manager. This would be set up similar to a sick day mechanic but you could track how often your employees are calling in sick. IN THE FUTURE, if possible, add an randomly generated figure that establishes the employees likely to call in sick. No one wants an employee that calls in sick all the time, its a hassle and can become expensive. Especially if you have already trained them up to 100%. This number generation would occur whenever a new applicate is created. Each one has a number that doesn’t change. You already have it occur each day obviously. But then you could have an additional number that fluctuates with their happiness. The more unhappy they are, the more likely they are to call off. The large majority of employees would have a very low number but there would be those random ones that just don’t want to work.