Beneful is very very bad food, I wouldn't let my dogs even sniff that garbage. That could very well be the reason for the dandruff. Consider feeding a better quality food. Fromm, Acana, Blue Buffalo, Blue Wilderness, Horizon Amicus, Go! Natural, Now, Merrick, Before Grain, Taste of the Wild, First Mate, Addiction...
Do not feed anything you can buy at Walmart, or Grocery Stores... Iams, Beneful, Puppy Chow, Ol' Roy, etc. Anything made by Hills, Purina, and Iams are crap as well.
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