I have 2 adorable 9 week old kittens.
The home they came from, from what I gathered were feeding them dog food once a day 

I feed them when I brought them home at lunch time. They ate a pouch of kitten food each. The same at tea time, the same at bed time (I didn't give it all in one go, but they seemed to still be hungry with less.
The next morning I fed them, one wasn't interested, the other gobbled and threw up.
After a week of lots of funny poops DH got them Applaws dried food and I mixed it with boiled chicken. It didn't make any difference.
On Tuesday the vet prescribed Royal Canin sensitive pouches (4) which lasted one day. They are eating two pouches a day each, so yesterday I got some more, but only have one pouch left.
The kittens are definitely pooping less.
Will going back to non-prescription food after 2 mean a return of the poops?
Is what they're eating excessive?