Chickens and wild birds eat other kinds of uncooked grains and seeds, without having that problem. There is no reason why rice would be different.I was under the impression that rice was no longer thrown at weddings because the wild birds would ingest it and the rice would swell when the bird drank water, leading to ruptured crops and death.
A quick google search turns up many pages that say the swell & explode thing is a myth.
So I don't think OP needs to worry about that specific problem, just about the fact the rice is a very long way from a balanced chicken food nutritionally.
Since chickens are birds, that was a reasonable thing to check: whether a danger to other birds is also a danger to chickens. But it turns out this one is not a danger for other birds or for chickens.If this has any semblance of truth, I would be concerned that uncooked rice might pose a similar risk when fed to chickens.
Just thinking out loud…