Variety good or bad ??

[breeze]

I recently went to pick up food for Bree and started a conversation with a couple of people about the food we buy (just to find out their reaction and comments). we are all feeding Eagle Pack Holistic select, but most of the people are changing to different flavors every time they finish the bag!!
One month chicken and rice the next duck meal & oatmeal, or Anchovy,sardine and salman meal (the anchovy and sardine they really don't like cause of the smell but the dogs love it ) or lamb and rice??
Is this good to change the dog flavor not the brand every month?? or should you stay with the same flavor??
does it not give them the "runs" Is it better for them to have variety?? or are they making the dog a picky eater??
Most of the people say their dogs love the change and they have no problem with their poop, and every time they come out with a new flavor they bring it home and the dogs love it