Welcome to JustAnswer, this is Dr. Christie.
I have a few quick questions so I can get some more information.
1) What is the kitten eating? Does it have a good appetite?
2) Have the kittens been dewormed?
3) Have the kittens had a physical exam by your vet yet?
4) You mentioned a white bowel movement. Was it normal consistency? Did you see any worms? Any diarrhea or vomiting?
Thank you for the information.
I would definitely suspect parasites. You will not always see them in the feces. 99% of the time, you need a microscope to see the parasites because they are microscopic. The adults (which are the worms you see) live in the intestines and pass microscopic eggs. I think deworming them may definitely help! Now there are certain parasites that a normal dewormer will not take care of. One in particular is called Coccidia. Puppies and kittens get this from their mom. It can cause weight loss, diarrhea, stunted growth, poor appetite, and overall ill thrift. I have seen one kitten or puppy in a litter have a problem with Coccidia and the others are just fine. There is no good explanation for this other than that paticular animal's immune system was ailing more so than the others.
I think the diet you have them on is really good! Kitten chow and canned food is definitely adequate for a 7 week old kitten. Certainly I would recommend having the kittens vet checked. A smaller poor doing littermate can also be due to more serious problems such as a heart defect or even a liver shunt.
You can definitely start with having a fecal checked at your vet's. If it should be coccidia, your vet can prescribe the medication needed to clear the coccidia, though your vet may require to see the kitten. Should the fecal be negative, I still think having the kitten vet checked would be the best thing, just to check if it may be something more serious.
I hope this helps! Please let me know if you have any other questions concerning your kitten!
Dr. Christie
veterinarian
veterinarian and pet owner
I am glad to hear she is doing fine and getting better!