Depends on what you buy! Grain free food is a good option....regular dog foods are usually made up of corn, some animals have allergies to corn and fillers that are used in dog food, so choose wisely and pay attention to ingredients.
Like everything else, much depends on quality and ingredients.
Yes it is ! The better ones are formulated just for dogs and what's best for them. I've fed my last two hounds this dog food and they stayed healthy and the one I have now really digs into it. You have to read the labels good for the proper diet.
Of course yes, but I suggest you buy it in good quality.
if its for your dog then yes.