How can i stop my dogs breath from smelling ?

Best thing to do for a dog who has smelly breath and yellow plaque on their teeth would be to take them to you're local vet for a dental. They are recommended once every 6 months to a year just like humans. Is the kangaroo and veggies diet helping with weight? This could be a contributing factor to the bad breath and tooth decay. Usually a good high fiber and low fat diet are ideal for over weight animals and of course healthy exercise. Brushing their teeth is an awesome idea and it's even better if they allow you to do it. Dental chews are also a good idea. But after all best advice I can give is 1) change of diet 2) Dental cleaning 3) Healthy exercise 4) NO canned food what so ever. (this food is too easily stuck to teeth and gums causing decay) and for continuing dental health hard crunchy food and once a week brushing. Hope this was helpful!