No problem with feeding raw at all if it suits your dogs, I have one delicate older dog who I am very careful with and hers would be cooked anyway. For the others its a practical issue of being able to feed straight from the freezer rather than having meat lying around in large quantities defrosting, as in the summer it attracts flies and in the winter it takes too long to defrost. When I'm on holiday I have a freezer box full and in any weather the top meat defrosts in time to be fed raw and the bottom packs are defrosted when I get to them. Just need to get to a petstore evey so often.(Every 5 days on hol for me)
If you have a reliable butcher who will mince and sell at good price that is super but dont forget they should have raw large bones as well and watch the qualityand dont always feed them the same meat and they should have some offal as well. The minced frozen packs, whether from landywood or AMP(petsathome sell AMP pricechoice) contain bone which is very finely minced and cook perfectly safely or of course can be fed raw. These packs also provide considerable variety of meat and offal and you should buy several sorts, it is so easy to give them variety like this. Dogs know that meat is what they should eat and all bowls are licked clean. I feed a little biscuit as well and find that makes an excellent, easy to feed, and reliable diet. As spoodle says there are non grain mixers for the gluten intolerant or of course one cooked bowl of rice will last quite a long time.
Please if you change diet at all, do it very slowly, a spoonful on day one of the new food and allow a complete fortnight to change over, otherwise you will have runny tummies.