Hello & welcome to the forums.
The first benchmark has to be a healthy dog. You need to be as satisfied as you can be that the dog is relatibelt healthy & absent of medical issues that may impact on appetite, impact on waste output, & free of worm issues etc. Dog must not be constipated, should be free from any internal obstructions......young dogs and old can eat all sorts of items & rubbish...sometimes causing blockages & appetite . I am assuming food was provided and removed if not eaten at once. Encouraging grazing can arguably cauze selective eating &/or remove food drive. Dog should also be drinking well, (some including myself mainly provide filtered water). I would regard a total lack of eating/drinking for any significant period as needing vet visit....... urgently if dog is lethargic or presenting with other signs of concern !
The following advice is assuming the above not being negative factors.......If not then address accordingly ideally seeing your vet asap.......If genuinely satisfied dog is healthy then consider the following............
I am somewhat suprised if your dog is refusing various foods.......Have you tried feeding treats ? I dont mean rubbish from supermarkets - I mean cheese cubes, liver cubes, dried lung, pure fish bites etc etc. .......Most dogs love food of one sort or another.
Assuming all was well with the dog then your kibble issues may have been down to overfeeding individual meals &/or daily amount. Orijen has realively high protein & less fillers than many foods so accidental overfeeding could cause loose stoo!s. Burns isn't as bigh on meat/protein content but contains rice & in relatively high ammounts.
There are mixed opinions on feeding grains with some alleging they are not a primal food source.... Others speak of grain intolerance. In my view allergy and intolerence are words used a little too frequently. i am not saying allergies & intolerances do not exist, but some could argue it is often just the case that some dogs suit certain foods better than others.
Going back to protein......the other considerarion would be protein sources, some will suggest single source protein foods are best yet others might argue that feeding one protein can cause later intolerances to newly introduced proteins. We cant ignore that a dogs might not get on with certain protein sources or food sources.
You state you were feeding a raw complete without issues. I am keen not to point finger at any particular brands or protein sources within brands as being better or worse than others.....(Note that I keep making references to compatability between foods and individual dogs). I have no idea if there have or have not been small changes to the manufactured composition of what you feed or if you have changed from maybe red meat to poultry etc.
Brief mention specifically re raw feeding...A reputable local raw feeder/supplier to me states that too higher bone content can sometimes cause constipation issues in some dogs.....her advice to me was to introduce offal/tripe or other lower bone content periodically - so as to keep things moving properly, (particularly if stools show signs of being over hard or excessively crumbly....(dogs stools are typically beirmer than if fed kibble)
Kibble wise I have fed various products.....lastly Akela. Cold pressed was seriously considered prior to me switching to raw complete (I fed raw to one of the dogs this before) am currently happily feeding nutriment but it is no secret on here that I change foods from time to time - My highest dog food loyalty is to our dogs not individual dog food companies.....however good they may or may not be. Cost cannot be ignored by me either.....especially when considering similar acceptable quality products.
If your dog is genuinely not getting on with various flavours from a particular manufacturer then maybe try another manufacturer. Whether looking at another raw complete, another kibble or other options such as cold pressed or air dried.....the directory has lots of different foods. You can enter dogs age & weight to get some idea re cost. Do consider that if you return puppy foods only then your result total will be significantly lower. Personally I dont think puppy food is essential. i woukd avoid foods for older dogs (sometimes called senior). I would also be mindful that some working foods are for closed season feeding so they might not provide enough of what a youngster may need.
If I was you I would be looking to get free samples (not usual for raw complete) or small trial amounts. You wont be wanting to waste food so don't buy large amounts. This will be best way to see what your dog will actually eat.
Any changes made must be your choice & for the right reasons.
Please return & update this topic.