Ok, I am not familiar with pigeons. Someone told me that feeding uncooked rice to pigeons will cause the crop to bloat. The story I was told was, that the reason people aren't supposed to throw rice at weddings is because it will cause the crop to swell, thus harming the birds.
I am under the impression that rice on a hard surface might cause people to slip and fall. Also the mess the birds would make hanging around the areas is the real and true reason for places to ban rice throwing. I do know for fact that most restaurants have signs posted around their outdoor seating areas, asking patrons to please not feed the birds because they make a mess.
Getting back to the uncooked rice. Will it actually swell the crop and cause a blockage?