The nest is made, but there are only a few eggs or other problems

The nest is made, but there are only a few eggs — or other problems
A successful coupling requires good preparation, every grower knows that. Yet around that time, questions regularly arise about failed broods: "What did I do wrong?" — and all too quickly the birds themselves are blamed. Of course, the birds may not be in top shape, but proper preparation should prevent that. Below are a number of possible causes, so that you as a grower can determine where things went wrong. I assume that the light preparation has been done correctly.
Birds keep fighting