Thank you for your question!
If your kitten has a big belly there are some important medical conditions to rule out some of which can be quite serious and it’s certainly worrying to hear that your other kitten was also sick and died with similar signs. I’d suggest having her examined by a vet who may perform some blood tests and also tests on the faeces to rule out intestinal parasites which occur commonly in kittens. Your vet may also use an ultrasound probe to see if the swelling is being caused by fluid in the belly or by something else.
It’s a positive sign that your little kitten is still eating and drinking. The sooner your vet can find out what has caused her belly to enlarge and can start any treatment the better for her health.
Dr. Alex Hynes