This is currently my fav chicken disease link, cuz it's got pics http://partnersah.vet.cornell.edu/avian-atlas/
From that site this is the closest pic I found to your little white bumps; http://partnersah.vet.cornell.edu/avian-atlas/search/lesion/445
In this one it is tumors from Merek's disease.
if you go to photo #4 in the link above, i think it does look similar to OP's photos.. if you had spread apart the intestines more during the photos? (photo is Marek's Disease)