How can I encourage her to eat her food?

Hi all,
I have a problem with my cat Villy. She is 10 years old and has a sensitive stomach. I normally feed her on royal canin sensitivity which is fine and suits her well.
However now that we have Roxy too, Villy is refusing to eat her royal canin and is sneaking the kitten food instead, which is giving her diarreah.
Iâ€[emoji]8482[/emoji]m going to try and tempt her with some boiled chicken to see if it helps.
Even if I donâ€[emoji]8482[/emoji]t allow her access to the kitten food, she will still refuse to eat her royal canin and will go hungry instead.
Iâ€[emoji]8482[/emoji]ve tried some other brands of food, such as Natures menu and Highlife, but they didnâ€[emoji]8482[/emoji]t sort her tummy out like royal canin did.
Does anyone have any suggestions or have you gone through the same situation? What did you do?
So far the vets have suggested trying her with plain chicken.
I thought that kitten food was supposed to be easily digestible so shouldn't be a problem?
Jessy

See this thread:

http://www.thecatsite.com/forums/sho...d.php?t=133698

the protein in kitten is liklely too high ... since she does well with her compare the two ... my guess is kitten has 5-10 % more protein and fat than her other formula..Probiotics can help if you can get them but in this case % are likely the culprit..

Sprinkle some brewer's yeast on top of the food. They love it for some reason! It's available at health food stores. Mine came in tablets but I crushed them up. Works every time!