stinky poop and eating like pigs?

My cats have eaten California Natural for about 2 years. About 4 months ago I switched to Felidae, well, because it was cheaper. Well they didn't seem to like it as much. I have 7cats, 7 bowls, each bowl gets a 1/2 cup in it each night. On the Felidae they took about a day and a half to finish the bowls. Well, I noticed that Captain was looking a little skinny, and he's myfat cat, so that's ok. And the food store was out of the big bags of Felidae and I hate buying little bags, so I bought the Ca. Nat again. Well, I put it in the bowls and they ate like I've been starving them for a year. This has been about 3 weeks and they're still eating like that. They finish the bowl in a few hours and whine for more. I don't give it to them, I make them wait. And their poop has been extra stinky too, and it was never like that before, even when I first switched them to Ca. Nat. Any ideas? Should I start giving them 1/4 in the am and 1/4 in the pm? Will the stinky poo go away?

Ihave no idea...when I switched them to California Natural the first time, they had been eating Iams before. There was no stinky poop then. But I did notice tonight when I got home from work thatI did not smell poop, so I think it might be getting better.

Mine did that when I switched him from Innova Cat to Innova Evo which is grain free......So much so that I swapped him back.....Oddly enough my new mother cat is eating the Evo Kitten/Cat formula more than she is wet food........Her poop is horrid but she ate the placenta's before I was even on the scene. She has gone from what ever crap she was eating to a much better diet so I am hoping she fills in....and lactates well.....=) Is that an ok food to feed them?

I would say the Evo cat is a greatfood to feed her.

Sometimes they are just adjusting to a new formula. I would not worry too much. In time it will go away.

well, the stinky poop has gone away, but they are still eating like they've been starved for a month.