Hi crazy4cats –
I would rotate to a new flavor every month or so rather than feeding one type in the morning and one type in the evening for a couple reasons. The first being, if you’re feeding one in the a.m. and one in the p.m. your dog, despite the fact that’s it’s getting variety, is getting exposed to the same ingredients every day. Many believe that continuous exposure to the same ingredients can result in allergies. So, for example, if you pick out a lamb based kibble from band x and a chicken based kibble from brand y and feed brand x in the a.m. and brand y in the p.m., your dog is getting chicken and lamb every day. If, instead, you feed brand x for a month and then switch to brand y the next month, your dog will get month long breaks from certain ingredients and not be exposed daily. The second reason, kibble should be consumed as quick as possible after opening the bag. The longer the bag is open the more likely fats are to go rancid, ingredients are to oxidize, etc. So I wouldn’t recommend having two bags open at once, I’d have one open and use it up because if you have two bags open it will take twice as long to get through each bag. Hope that helps answer your question!
