Sudden eating changes in cats

My cats have been on the same food for a while now, I switched from California Natural to Fromm Gold when Natura had their big recall, and they have all been eating it and doing well. Within the last few days my second youngest male, almost 6 years old, suddendly stopped eating the food and will only eat the dry dog food. He'll also eat cat treats and canned food but refuses to touch the dry cat food. I tried a different brand and flavor tonight with no luck, he wants to eat the dog food. Also one of my females, 7 years old, has stopped eating the dry, but she also won't eat the dry dog food. She ate her canned food at lunch, but when I tried to feed her the dry tonight she backed away and acted like she was afraid of her food dish. The other 4 cats that are eating the Fromm dry cat food don't seem to be having any problems with it. My oldest is on a different food that's easier to chew and they won't touch that either. Has anyone ever had this problem before? I've had both these cats since they were young and never encountered this problem.

They may have changed the formula and that may be the difference.  Have you opened a new bag recently?  I'd look at introducing a different type of food and/or increasing their wet food intake.

I did open a new bag recently but the formula is the same. I tried a different food on Toby tonight and he won't touch it, he only wants to eat the dog food. I wasn't having problems with Lilly until tonight. They both ate their canned at lunch. I fed Lilly some treats a bit ago and she ate them right away.

I am dealing with the same thing with my girl DeeJay right now, we are trying every food under the sun to try to get her to eat more than 1oz.  I am taking her to the vet tomorrow just to be safe.  Sometimes even though the formula is the same, it can change from bag to bag, they only have to update it on the bag I think every 6 months.

Sounds to me that they plain do not like it anymore...  Try something else? Or keep feeding wet food as that's going down ok? Am not a fan of dried anyway.  I think persisting with something they will no longer eat is pointless personally.

My cat is very very picky. He eats wet, but I have to give him different flavours and brands all the time. If I feed him the same thing twice in a row he looks at the bowl with utter disgust, even tho he ate it happily earlier - and I don't blame him, eating the same thing is boring!! Luckily switching doesn't cause him an upset tummy, phew.

They're both back on their food tonight, none of the others seem to be affected. Sometimes I think they like to worry me for no good reason.