I am in a pickle here...

Blue, before Rex came along, was doing well on a Senior cat food. Since he has had the diarrhea and been diagnosed as hyperthyroid, he has had a pretty bad weight loss.

In an effort to control both the diarrhea AND the weight loss, my vet suggested changing Blue's food back to the Senior food I was feeding him before (Purina Senior). Though it is not the best food, it is something he has eaten and done well on before and something we know will be "safe" as far as diarrhea...and that is the most important thing right now. We will worry about "good quality" switching after he gets this behind him.

Here is my quandry, though... Blue has always free fed on his dry food with occasional wet food meals (once a week or so). But Rex is not a senior cat...he is a KITTEN! Rex eats out of Blue's food bowl - apparently he likes the old cat stuff better than his kitten food. I can't let Blue get in Rex's food because of the diarrhea issue and the fact that Blue has never eaten that brand before. Rex has the diarrhea too and, ideally, I would go back to feeding him the Hills Science kitten food he was eating at the shelter (again, back to something we know he could eat/tolerate without diarrhea), but if I free fed Rex, Blue will eat the kitten food too.

So, which is better - if I can't switch to an "all life stages" food right this minute, should I cater to the older cat with the senior food and just let Rex eat it too or should I cater to the kitten and just let Blue eat it too? Or should I put both kinds out and hope the cats figure it out?

HELP!

If it is at all tolerated aim for the kitten if you cant separate and meal feed

I'd probably let them free feed on the senior dry food, and add wet meals where you can give Rex kitten food, and Blue... I don't know what you feed a sr. kitty with hyperthyroid. But whatever wet food is appropriate.

I'd also consider finding a stinkier kitten food, and calling Rex to the bathroom or something and putting kitten dry food out for him in there whenever you can, and hopefully you'll get him filling up on kitten food, even though he may nibble at Blue's food left out for free feeding.

I's go with the senior food, and like LDG said, supplement that with kitten/wet for the kitten when possible. Also, check with your vet, but you can give the kitty Nutri-cal to make sure he is getting all his vitamins.

Senior food won't lack for vitamins, its the protein and fat that is different.

Are scheduled meals out of the question? I found it's really the only safe solution with food issues. Mind you I have one that will eat anything and regurgitate if it has something he shouldn't have and another who wants to eat everything but can get extremely watery stools if he eats someone's food that has chicken. Oh and another on C/D. It's trying, but we have a routine here now. Wet food is a big part of their diet, so I agree with working that in. Through experimenting you'll figure out what can be finished in one sitting.

Our biggest problem right now is just stopping the diarrhea/loose stools. Rex has had formed poo for 2 days straight now (woo hoo!) and Blue hasn't gone much at all (hadn't been eating much until I fed him some chicken off my plate last night). Since Rex's diarrhea has stopped while he was eating Blue's senior food, I am terrified of even trying to add in wet food for him right now!

What wet food is generally well tolerated and formulated for kittens? Any suggestions. I could try adding in wet Kitten food for Rex a little at a time and see how it goes. I know he will gobble it up...I just worry about the stools.

I personally wouldnt feed senior for a hyper-t cat - they need as many calories as they can, and most senior foods are lower in calories, so he will need more food to maintain/gain weight, which has more risk of causing diarrhea. It might be better trying to find an all life stages food for the pair of them - and the diarrhea could be due to the hyper-t. i know how hard it is, i have an IBD cat, it has taken 6 months to find a dry food that he can tolerate, and I am gradually building up how much he gets (he is up to 10 pieces a day)