Honestly, I don't even know what "richness" means. Is that supposed to be protein content? I really don't buy into that idea too much. When Nemo had severe intestinal issues (likely intestinal cancer) which led to chronic diarrhea we were able to get him to do well on raw food for a decent period of time which is relatively high in fat and protein (I have an integrative medicine vet) where the specialist recommended the "highly digestible" science diet stuff. He had some food sensitivities before that, likely chicken (not raw but in processed foods) and corn. If your dog was having food issues before the incident then I would suggest doing an elimination diet and try a novel protein source and see what happens. I've been feeding my dogs the Sophos complete dehydrated raw food when travelling the past few weeks and it has worked well. You can buy small bags of it to try it.
The research with probiotics and people isn't really conclusive or straight forward either but many find benefits with them. But it's one of those things that might help and really can't hurt too much other than your pocketbook and maybe some gassiness with your dog.
Which ID food was it? What was the protein? Which Fromms were you using? In this case you may just have to try a less than ideal food but better than the ID to get him more normal and then transition back to a better food.
One thing to consider is the Nutriscan test (I haven't looked back in the thread to see if it was brought up before). http://nutriscan.org/ It's a bit pricey if you do both panels but it might indicate if he has sensitivities to any particular things and then you would know to avoid them in diet selection.
And a trainer can help you set up the situations to desensitize and countercondition if you aren't able yourself to do it. Just be clear in what you want from them up front. You want modify his behavior not just manage it. Although you will always have to do some level of management.
Read Jean Donaldson's "Mine". There is a protocol there for resource guarding. It mainly applies to humans in that book.
For now you have to manage. So crate the dogs while they are eating, even if it is a treat. Or at least one of them. And no one can give him food except you. You will just have to be mindful of that.
Starting just by yourself with Oakley is how you should start with any of the behaviors and then move up to having a trigger present. You can certainly make the situation better but I don't know if you can completely fix it, that is likely dog and situation dependent.
I can't take credit. I'm like a sponge– I listen to everything and use what I can. If something works, I keep at it, modifying where it makes sense, and discard what doesn't work.
LIMA is a new one to me, but I agree with the philosophy. What I have learned is that many "surefire" things are ineffective with a challenging dog. I would never intentionally hurt Ava, but I'm sure the crate training is causing her distress. I feel I have to do it, though, in the kindest way possible. And better me than a trainer, who might not treat her with the same care and patience.
I admire you for going to the level of effort you are. Not a lot of people will do that.
I like to think in terms of LIMA, least intrusive, minimally aversive which is the philosophy that the IAABC uses. I doubt they define aversive as pain but that is where my mind goes as that is what I want to avoid as much as possible, be it mental or physical.
I will be there. We will have a rally course set up so people can try it out. People will be there to explain how it works. Also there will be a nosework demo at the end. Several club members are currently doing nosework with their basenjis and absolutely love it.
Part of the issue is that your puppy developmentally is way too young at 5 weeks to be leaving its mom and the other puppies. So, beyond this issue, you will need to put some major focus right now on teaching bite inhibition and socialization to make up for it the best you can. This is a very different situation for the puppy and it will need time to adjust, it's not used to being alone. That can be difficult for older puppies but I imagine it is even more difficult for younger ones. You will need to work on the puppy learning to be alone in shorter increments and you can use crate training techniques to help. Also try to find a way to have the puppy be alone for shorter periods of time at this age when you leave the house. Good luck.
I use this type of kennel for my dogs in the basement. I like them because they are modular. So if you want something bigger than a 4' x 4' kennel you can just buy extra panels to make it larger if you want. Very easy to put together and to take apart. It's bigger than a crate but still something you can use to confine him and keep him safe.
You can build a positive association with a crate or kennel but it may take a while if he already has a bad association with it. Changing what you are doing now and transitioning him slowly to something else could make it easier.