Also if anyone who feeds raw, how did you prepare your dog for the hospital food that they feed. I'm assuming a hospital has their own protocol, rules, restrictions concerning home prepped meals being brought in. I'm not that far into this yet to ask directly so it would help to hear experiences and I really don't want him off of raw.
Most dogs have terrible appetites after anesthesia, so they need sometimes need some extra-delicious food if at all possible for the post-surgery recovery.
As for what they'll take...you'll have to find out their policy! It really varies. I've been through a lot of aggravation with with a specialty hospital over feeding -- my dog literally gets bloody diarrhea on kibble (even RX kibble!), and trying to convince vets who don't know his history of that is not easy.
My regular vet clinic will feed whatever I bring -- even raw. I board there too, and they're really good with my allergy dog. I can bring them quart-sized, frozen zipper bags containing a preportioned meal, and they'll pull one out of the freezer to thaw in the fridge as they use one, so one is always thawing, and the rest stay frozen. The staff is smart, and good. They saw my dog at his sickest and know how big a role diet played in fixing his issues.
OTOH, specialty hospitals are a whole other thing. Before VCA was bought by Mars, their regional specialty hospital (which is also an emergency 24-hour critical care hospital) would at least feed the freeze-dried raw nuggets I brought for after surgery (Nulo was the brand). I bought them specifically for surgery recovery as my guy loves freeze-dried meat like it's a treat, and I was trying to be respectful of the clinic staff who may not want to handle a bag messy, raw meat. My dog easily goes off his food for days, so it was the one food I could be pretty sure they could coax him to eat that wouldn't upset his GI tract....and it would be easy to feed.
After the Mars buy-out, VCA rejected the freeze-dried nuggets because the bag said "raw." Here's what the bag looks like:
The same vet tech who had fed it two weeks earlier rolled her eyes and whispered an apology while telling me her manager was unyielding due to corporate policy. She would get in trouble if she even took the bag into the back because Mars management was treating it like it was infectious. So I had to leave the hospital to go find 95% beef canned food -- it was the only thing I could figure out that they wouldn't balk at, that my dog was also likely to eat.
I didn't try Ziwi Peak with that clinic only because I didn't want to spend so much money on a bag of it only to have them reject it too -- the Nulo was expensive as the bags are small.
So...YMMV. If they'll let you bring in a bag of Ziwi Peak dehydrated food or Nulo freeze-dried, it's as close as you can get to raw while still being in a bag and tidy to feed (which may make the staff more comfortable).