I was wondering ( after alot of reading) are cats fed grainfree diets more likely to get blockages and UTI's? doe the grainfree cause it?I have my cats on both grainfree dry (natures variety instinct) and also a grainfree wet( evo,and by nature) should they be getting some grains?They free feed the dry ( they really don't eat much of it) and they get about 5 to 6oz of wet each a day.Is instinct a good grainfree dry?