if Shivon had not vomited prior to her fast, i'd be less concerned. Just skipping a meal now and then is fairly benign behavior for some dogs.
for MY dog, i'd freak out, as my dog has most marvelous appetite you ever saw...he has never skipped a meal in his life, that i can remember, (except for once when he decided he was SO DONE with eating raw eggs on his kibble on Sundays, and he refused to ever eat one again. lol.)
Buddy happily ate raw eggs every sunday,
for a long long time,
and then
suddenly decided raw eggs were disgusting
, and THAT, was THAT.
He even seemed to worry for sometime after, if i might be sneaking in a raw egg into his food for sometimes afterward, approaching his dog bowl very cautiously, was hilarious.
but, since your Shivon IS a princess, perhaps is no big deal,
one(1) meal anyway.................a whole day,
would worry me, and two days would def worry me a lot.
Sara once taught me, that dogs were never intended to eat twice a day, every single day, and that she, on purpose, skips a meal for some of her dogs, every now and then, just to perk up their metabolism. so now, i do the same thing, esp if buddy is looking a bit slower, and wow, it does seem to perk him up!! this also works on ME, too!!
so maybe Shivon just does that???
also, lots of dogs do NOT need to eat as much as the bag says to feed the dog.
keep those foods, who knows, Shivon might resume eating them later on. If nothing else, you can donate the leftovers to the dog pounds. It will be the best food THEY'VE had for a long time, i'd bet!!