What is the definition of excessive egg-laying? My pekins lay an egg almost every day. I'm guessing at least 5-7 a week since they started laying Fall of 2019. I didn't know this was a concern!
It is hard to determine what "normal" is in a bird that has been bred far from what it's wild would be like. Generally, the term excessive/chronic-egg laying is used in psittaceous birds, such as budgerigars, or cockatiels, when the hen is repeatedly laying eggs (instead of a clutch); overtime this can cause a calcium depletion in her body, which then promotes the onset of other difficulties.
With ducks and most poultry, they have been specifically bred to achieve greater eggs they can produce each year. Frequently, egg production slows down after one year of age, and during winter when the hours of light are low. However, some hens may continue to lay eggs every day; with owners that care less about the health of the bird, and more about the egg, the birds are usually left alone, but over time that can promote some of the conditions mentioned. For the overall health of the hen, it's best to discourage egg-laying, and if not, ensure she has adequate calcium supply in her body.
In short terms, the way we have evolved these birds to be, and lay so many eggs, in time, is not good for their internal health. If your bird's health is a primary concern, some sort of effort put into supporting her daily egg-laying lifestyle, or decrease the number of eggs she lays may help prolong her life.