when to feed expecting Mama kitten food??

Not being a breeder this question got me today... When to put expecting Mama on kitten food??

As soon as you know she's pregnant. She needs the extra calories and protein for her babies.

If the cat is a queen in a responsible breeding program, I'd even say put her on kitten food before mating. But if it's an accidental pregnancy situation, the question is kind of moot because the cat should definitely be spayed in this case.

I have always done it AS soon as I know shes preg. They need the extra proteins and Vits ASAP

Thank you for the quick replys