Okay ... reasonable question ... went and looked it up for you regarding
instant rice (which has been precooked, then dried and packaged, like Minute Rice).
University of Kentucky biologist Jim Krupa performed studies using
instant rice and whole-grain rice and found no issues or exploding birds.
http://mentalfloss.com/article/31421/does-wedding-rice-really-make-birds-explode
It was also discussed in Delaware's Mensa publication and others.
So it looks like even
a day of instant rice (raw Minute Rice) fed with free-choice water, which our chickens are supposed to have anyway, is not going to damage my chickens, just my pocketbook and their energy/vitamin/protein intake.