I bought a bag of Taste of The Wild- my dogs really enjoy this food... It was a new one Roasted Lamb http://www.tasteofthewildpetfood.com/products/dogs/dry_food/sierra_mountain_canine_formula/ for some reason they wouldn't really eat it at all. Junior's tummy was just growling and they got the poo's from it. My dogs are not picky... I even made it soggy with water which they love and still didn't care for it.
I have had a bad batch of Arden Grange dried food and my bitch wouldn't eat it. I sent it in for analysis and it had gone mouldy due to water damage. Contact the company. Has it got a bad smell to it? Perhaps they just prefer the other flavour.
I bought a bag of food from PAH. Think it was Proplan but can't remember for sure. The top looked OK but my girl was doing a lot of sniffing rather than hoovering the food which is her usual way. So I dug down into the food and found some mouldy pieces. Took it back for a refund, no questions asked but she was right to be fussy over it.