What increases mortality rate?

Question
The first time  two of my Does dilivered after one months and five days the litters died all.After this incident i mate again one doe that delivered 9 litters when they were one month two weeks ,withing two days all died after i gave them cabbage leaves.

Answer
You don't give baby rabbits anything to eat while they are still nursing the first 4-8 weeks.  They will begin to eat hay partially in the second month.  No veggies or fruits until at least 6 months old.  You can kill them giving them veggies and fruits when they are young, as you have done.