Chronic diarrhea in kittens

Hello, all! I'm a newbie here but I've been reading threads on here for several months.

My situation: I adopted two kittens on Feb. 12 who were born at the beginning of December. They had been with mom and siblings at a foster's for several weeks, but they'd come from an animal shelter before that. They were both fixed, given initial shots, and dewormed before I got them. Their names are Alfie and Beatrice—Alfie was the largest in the litter and Beatrice was the smallest. 

They've now been with me two months now and they have yet to have a solid bowel movement. They've never acted sick and they both enjoy eating (especially tiny Bea!) and playing. But I can't get the diarrhea (sometimes bad, sometimes better, never solid) under control.

In a nutshell, after they'd been with me for two weeks, Beatrice started leaking diarrhea. We went into the vet and they tested positive for coccidia. They both (and their 17 year old kitty sister Lucy) went on a round of Ponazuril. On followup coccidia was gone but Beatrice tested positive for tapeworms, so everyone got a dose of Profender. On the next visit fecal tests were clear but they were given a second dose of Profender to be safe and five days of Panacur because they still had diarrhea. That was two weeks ago. I've also been giving them Probiotics for two weeks now.

I feed the cats super high quality grain free wet food. Lucy (the 17 year old cat) will only eat dry food, so the kittens do get into her grain-free dry kibble. I've switch among brands (I use Weruva mostly) and this weekend I bought frozen raw food because I read that's great for intestinal problems, but they won't touch it. So I have mixed their food around a lot recently. 

Last night Beatrice left a spot of diarrhea on me for the first time in a while and she is now leaving her runny poo uncovered in the litterbox. The smell continues to be terrible. I don't know what to do. I have already spent a small fortune at the vet as well as on cat food. The vet said the next step would be a more sophisticated test to look at parasites and other GI problems (I think they've been doing flotation tests?) and that test on its own is $240. I'm between jobs and foolishly did not anticipate these mounting bills. The vet  wanted me to feed the kittens Science Diet kitten food, which I'm not doing because of grains in the ingredients. The food I feed them is supposed to be good for all life stages because of its protein/nutrient balance. So, diet-wise I'm doing my own thing but neither my diet solutions or the vet's medications have stopped the problem. I feel like I am just throwing money I don't have out the window. 

It scares me that, although she's a feisty, rambunctious kitten, tiny Beatrice is the one having more problems. Yesterday she started sneezing and I'm now giving her L-Lysine, but I'm scared that I'm losing a battle for her health. I dropped off a Beatrice stool sample at the vet on Friday and it was negative, but then the diarrhea flared up again.

Anyway...I'm at a loss. I've tried everything and I don't know if I should just be patient or suck it up and go into the vet again. I'm concerned that they're being given more and more toxic chemicals by the vet that are not helping.

Any suggestions, comments, or insight are appreciated!

Below: pics from when I first got them two months ago (left) and a few days ago (right). They're definitely growing, even with the diarrhea problems.

i would honestly follow the vet's advice and switch to science diet or another dry cat food before doing any more tests, regardless of the grain content. cats and dogs have evolved to digest grains so a little won't hurt them- it's just when you get a lot that you have a problem.

i personally sing the praises of Royal Canin (https://www.royalcanin.com/) cat food because it has seen me through many difficult kitty illnesses among my fosters. esp its digestive tract type. and believe it or not, Purina kitten chow works pretty well too.

it could be possible that something is stressing them out, as well. i've had kitties have super leaky diarrhea due to stress. do you have any other animals that they may not get along with? do they get along alright with Lucy? being sick for so long could have caused them to be stressed out too.

The test your vet is talking about is the PCR test.  I know it is expensive but if you can possibly afford it I would get it done.  It can find parasites and bacteria that the float test can't find.  It actually checks for the DNA signatures of parasites and bacteria that the float test isn't able to detect.

I second the advise about the science diet-or another round of wormer-usually the wormer is done in 2 sessions.

also stop changing the food so much-stick to one kind/flavor for a week to see if it calms down.

you can get plain canned pumpkin in the bakery lane in the grocery store=not the pie filler mix but plain ol pumpkin-1/2 teaspoon or less would be good daily=-it helps both types of poo problems.

also vet has probiotics that can help=not sure if its safe for kittens but I also heard non sweetened yogurt plain ol kind also has those active cultures to help gut bacteria-I think the main thing is keeping the food one type and see if it helps.

one of my cats is very sensitive-if I feed something new-yep she gets yucks.

and also try to get that PCR test done-you could call around other vets to see if you get get a better price.

keep us posted.

I'm sorry to hear about all the trouble you're having with your cats' digestive systems. I noticed you're feeding your kittens a lot of Weruva and am not sure which specific foods they get but wanted to mention that, though it's not that common, some cats -- including one of ours -- are sensitive to potato, an ingredient Weruva puts into a lot of their foods. When I made the connection between potato and Edwina's gassiness and vomiting, I took potato out of the cats' diet, and Edwina's issues were reduced to nearly nothing. (She still eats too fast sometimes and then vomits, but that's a whole other issue!)

FWIW, if you're looking for suggestions for later, after your kitties' stomachs settle down, our cats' potato-free, pea-free, carrageenan-free, and grain-free canned foods include certain foods from Weruva Cats in the Kitchen, Merrick LID, Tiki, Bravo, Hound & Gatos, Soulistic, and Nutro Natural Choice. They also eat three brands of raw food: Primal freeze-dried, Rad Cat, and a little bit of Stella & Chewy's. They have pretty sensitive digestive systems so it took some months to get them into a good rotation of foods that don't contain ingredients I feel uncomfortable with... and that I could be sure would agree with them.

I hope you're able to get your kitties' stomachs in better shape soon -- it's so hard living with cats' digestive issues!