My kittens are dying

Question
My cat had 3 kittens 5 weeks ago, last week one of them just stoped eating we tried to feed him with a droper but he wouldn't eat he became week and by late night he died. Now another one is doing the same, she is breathing hard and just lays there, their is a small swelling in her tummy. I think it might be to late to save her, but I would like to know what I am up against so that I can save the last one. He seems to be doing fine, and he is and has always been much bigger than the other two.
Thank you
Sharrie

Answer
It could be a number of things...most commonly would be infestation with intestinal parasites or FIP causing the bloated belly.  Your best bet is to take those 2 kittens and momma to the vet for a check-up.  If mom has not been checked for Feline Leukemia, then have her tested.  Also, checking a stool sample is a good idea as well.  They could be getting sick from viral or bacterial infection as well and without examination, it is hard to say for sure.  Getting an autopsy on the kitten that died could provide insight.  And I would definitely recommend spaying momma in case there is some genetic defects.