which is the best dog food ?

This is a quite difficult question. I don't know the real answer, but as you were told above, Pedigree is a no-no. You could find some answers here: http://www.dogfoodanalysis.com/dog_food_reviews/

NOT Pedigree Chum. I wouldn't feed it to my worst enemy, let alone my best friend. the ingredients are terrible. I find it depressing how it's considered a quality food. I do approve a lot more of the likes of James Wellbeloved and Burns for biscuits, and Naturediet for meat. Naturediet is made of meat that is legally fit for human consumption. no condemned meat there. you know you sometimes see blue bits in dog food meat? that's where they dye condemned meat to stop it entering the food chain.

I'm not sure of the brand, but there's a dog food made by a company called The Honest Kitchen and it's extremely healthy for dogs. It's a green food that you add water to. It's very different from regular dog food. Do not feed a pet Iams. Iams is actually a horrible food for pets.