I have a year old westie and I am thinking of changing to complete food which is best?  Had a look in pet shop but there are so many all the people I know feed tinned food.  Also is it still ok to feed chicken and tuna occasionaly or does this defeat the purpose?

Think you have a good read of the packet, then you pay your money and take your choice. And yes you can replace to odd meal with a treat meal if you wish or sometimes add a little extra to the food.

There is really no ONE best commercial food for ALL dogs.  If I were to feed commercial dog food I would try and feed one with the least ingredients as possible, with the least additives etc as possible.  One that has been fed with great success I think on this Forum is Burns which is a complete dry food and Nature Diet which is a complete wet food; both contain only meat, rice and vegetables.

Remember, if you feed tinned food 70% of it is water and you paying for a tin.  If you feed pouches these contain items such as plasticisers to keep the food "moist".  If you feed dry than the major part of the food will be cereal based.

Dogs do not need food that comes in "shapes" (that is for out benefit) or colours (they are colour blind).

Tinned sardines, pilchards, mackeral etc are extremely good for dogs being high in Omega 3s.   You can feed one tin instead of a meal.