What book was it? I thought that was a myth and honestly, it sounds risky...a cat in heat WILL find a way out if she's determined enough. But I don't know, I've never had a female cat.
As for raw diets, keep in mind that your vet isn't a nutritionist. Most vets are sadly misinformed when it comes to homemade diets, often fearing that the diet will be unbalanced. I understand those fears but if you research, the diet is the best thing you can do for your cat IMO
. These links should help:
http://feline-nutrition.org/nutrition/how-to-transition-your-cat-to-a-raw-diet
http://www.rawfedcats.org/
As for raw diets, keep in mind that your vet isn't a nutritionist. Most vets are sadly misinformed when it comes to homemade diets, often fearing that the diet will be unbalanced. I understand those fears but if you research, the diet is the best thing you can do for your cat IMO
http://feline-nutrition.org/nutrition/how-to-transition-your-cat-to-a-raw-diet
http://www.rawfedcats.org/