chickens & Cat food

HI, This might sound like a strange question but here goes.
Is it ok to let chickens eat cat food (meat) my 3 love it. IF i let them out for a walk in the afternoon and forget to take cat bowl in they demolish it.
Thought I might try giving it to them with Limestone flour in as 1 of the girls is laying very thin shelled eggs,
They have layers pellets , grit and oyster shell but stillhave the problem, the 1 that is laying the thin shells is only a year old.
Many Thanks