hi Jezebel. The Chicken Soup is probably be OK. maybe a bit high in carbs? but i think under 10%.
The Earthborn ( is that what you mean? I know a food called Earthborn. Is there a different one called Earthbound?) unless it is their grain free kind, is way higher in carbohydrate than I would want to feed -- at least according to this http://www.naturespetblog.com/2011/07/earthborn-holistics.html it is 36% carbs. ( which makes it over 10 times what a cat's natural diet would be.) That one has got rice and oatmeal and peas. that's a lot of starch. If she started eating more of that, that could be what is giving her some loose stools. ( Actually even the " grain free" dry foods are usually pretty high carb for a cat. The Earthborn grain free dry is i think around 17% carbohydrate which is similar to most of the " grain free" dry cat foods. )
It may be that her poop first got runny just because of changing.. then firmed up... then if she started eating more of the dry food, that may have caused it to get soupier again. Dry food nearly always has more starchy ingredients -- grains and/or something like potatos or peas -- to make the pieces form into kibble... and cats' bodies are not made for eating such foods, so if she started eating more of that, it could be upsetting her digestion a bit.
You could try going back to more canned food.
Another thing you can do is add a bit of canned crushed pumpkin to their food. just like a spoonful. . It may not seem to make sense but that can actually help with both constipation and runny poop.
Another idea is probiotics. Here is a recent thread dealing with that http://www.thecatsite.com/t/262587/probiotics-search-human-grade-and-cfus
Just in case you are curious here is what I usually feed my kittens . ( I'm not saying these are perfect or the only acceptable commercial foods )
Canned: Wellness in chicken or turkey
Merrick Purrfect Bistro pate style in chicken, turkey or duck.
Raw frozen: Natures Variety Instinct venison
Dry : Natures Variety Instinct Chicken
Those are " all life stages" foods.
I do find that the raw helps to firm up their poop.
Ideal would be probably homemade raw IF carefully balanced and prepared. .
If you are interested in making your own see the nutrition forum's section on Raw and Home-cooked food http://www.thecatsite.com/f/65/raw-home-cooked-cat-food
A great site from a vet with a lot about cat nutrition http://www.cainfo.org includes a section on Making Cat Food with recipes .
Another recipe from a breeder & author of Raising Cats Naturally http://www.blakkatz.com/recipes.pdf
Otherwise .. if looking for commercial food, you want high animal protein, moderate-high fat, very low carb. carbs definitely under 10% of calories.
a 6 wk old kitten should eat about 4 meals a day.
A link to a chart with nutrient info for many canned foods ( not yours though --maybe the company did not give her the data?) http://www.catinfo.org/docs/FoodChartPublic9-22-12.pdf
Edited by maewkaew - 9/9/13 at 4:56pm