Answer by  
                                                                                          mammakat (11147)
                                                            
                          
                          
                                                          Soy seems to be a big factor in this, as are feed that is "acidified" for preservation, meat and poultry "byproducts" contain organs that are high in oxalates. Don't use "prescription diet foods" and actually, any dog food that's not human food grade contains ingredients that can cause oxalate crystalization.