Here are some reasons why a cat's milk might dry up:
* Stress: Moving, new pets, or changes in the environment can affect a mother cat's milk production.
* Illness: A sick mother cat might have reduced milk production.
* Nutritional deficiencies: If the mother cat is not getting enough nutrition, her milk production could be affected.
* Age: After a certain period, a mother cat's milk naturally starts to decrease.
It's crucial to seek veterinary advice if you think your kittens are not getting enough milk. They can assess the situation, check the mother cat's health, and provide guidance on how to best care for the kittens.