Cappy, no I meant variety as in- all kinds. "One food for life" is a myth designed to promote brand loyalty at the least and possibly has more...concerning intent < no I don't trust Big Dog Food - "Big" as in same idea of "Big Pharma"> I would not get any dog food from Blaine's F&F or any big box store but as you said you have no holistic shop...adding in fresh food would be a good idea. Even when I fed kibble 14 or more years ago <since than have not fed any> I rotated through 3 or 4 brands of kibble such as the Nature's Variety you mention, Innova <there was no "grain-free" back then>, Wellness.... and added in other things. When looking at kibble or canned dog food, look for a named meat and/or a meat meal to be the first and second ingredients, or at least in the top 3. If you see <making up typical ingredient list>:"turkey, potatoes, sweet potatoes, rice bran, canola oil, egg product..." - that's mostly potatoes and rice - mostly carbs, very little meat. Avoid it. Also, less sugary carbs such lentils or legumes are less negative for a pet carnivore than sugary, starchy items like potatoes. <and realize "egg product" is NOT the same as for-human-consumption-eggs you'd find the grocery store>. Avoid anything with corn, wheat or soy for variety or reasons. Like WDYS! suggested, avoid artificial colors, flavors and preservatives, all of which are potentially carcinogenic. If something is pink or turquoise or yellow - that's usually fake, not from a natural food dye. Don't look at pretty picture of bits of steak, carrots etc falling into or sitting next to the dog's dish. That's marketing hype and inaccurate to what -really- goes into "dog food". Read the ingredients label. as for your little Chi - you could try a few different things, in tiny increments, watching to see if there's a change in relation the new item. Try one new thing at a time. I would try the cottage cheese - or some other animal-based protein - regardless of stool - but again, tiny amounts. And realize that some dogs don't do well with dairy. I'd add in probiotics and enzymes with a new food item also if the dog is not used to eating fresh food or trying new foods - which actually is what the dog is designed to do. For crumbly stool specifically you could try: canned pumpkin <NOT pumpkin pie filling; can work for constipation or looseness....or small amount of fish oil < a supplement I suggest regardless because processed dog food is too high in omega-6 fatty acids, which promote inflammation and disease>....or again for the stool you could try the probiotics and enzymes. Any combination or single of the just-mentioned *may* help - but it may not a quick thing, especially if this has been happening for some time. Remember to just try one thing at a time, maybe for a week to 10 days - unless consistent and adverse effects - like, you now have runny or liquid poo that isn't resolving after a couple of days.
Cappy! I enjoy discussing that kinda thing - that was my job at the holistic pet supply shop where I worked previously. Any other questions no problem to ask - much respect to you also 
