1. The age of the duck – as they get older the amount of eggs may reduce.
2. The health of the duck – illness or parasites can hinder laying.
3. The time of year – the length of daylight can affect egg production.
4. Changes in the type of food given – this may cause problems as the nutritional content of the food may vary.
5. The introduction of new birds to the flock – this may cause undue stress for the duckss as they re-establish a pecking order.
6. Significant changes in routine – can cause stress for the birds.
7. Housing conditions – unclean, overcrowded, dark and cold conditions can cause stress and or illness which may affect egg production.
8. Handling and movement of the birds – transporting ducks, overhandling, incorrect handling and sudden handling may hinder laying if this causes stress for the birds.
9. Vermin and predators – the presence of rats, mice, cats, dogs and foxes may frighten the birds or cause undue stress.
10. Become broody – the duck stops laying because she wants to sit on a nest of eggs and hatch them .

Hope this helps and hope that your ducks starts laying again soon.
Kind regards
sara @ farmingfriends