They are going to be fairly gassy regardless.

You can add a Tb of non-fat plain yogurt to the feed daily and it will help eliminate a lot of gas.
I would suggest you look on this site for diet guidelines. You can also do an internet search for BARF diets. They can be a bit of work to set up and maintain properly or if you buy premade they are fairly expensive. There are kibble diets being made now which come very close, IMO, to the ready-made BARF diets available. They can be ordered over the internet if you don't have a supplier in your area. They aren't cheap but you are paying for meat and other quality ingredients - not filler and corn/grain.
You should not feed your dog raw and kibble at the same time - they have two different digetive times and can cause excess gas.