Thanks all, for the advice. We fed Charlie a white rice-boiled chicken breast diet for most of last week, and thankfully it seems his systems are back to normal. But… we did have an interesting observation that I wanted to share and get your feedback on.
While he was getting the chicken and rice, Charlie seemed a bit more 'tame' than usual - calmer, more restful, less jumpy. We attributed it to him being hungry and weak from the diarhhea and the low-energy diet.
As soon as we added even a bit of usual kibble back to his meals, we noticed that his usual 'edginess' came back. He's always been a restless, edgy boy - ready for action at any minute - highly attuned to about what's going on, and what it might mean for him - and likely to create some action if he's bored. His crankiness came back too. Anyway, all this made me think that perhaps his kibble is causing some of his restlessness, edginess and crankiness. Is this possible? Or is it more likely that he's just feeling more like his usual basenji self again?
P.S. Charlie's on Canidae chicken and rice kibble. We usually add a spoon of pumpkin.