That's not a "theory", it's not even a scientific hypothesis.
It's somebody's fantasy, or given the article is from poor, vegetarian India it could be a journalist's wet dream of how humans might develop to eat unprocessed grains.
Sure, beaks are OK for birds who have severe weight restrictions, but not necessary for ground-bound humans, unless we first develop to fly -- and then we wouldn't need other heavy appendages like brains, of which this article's author has obviously already discarded his own.
persevere: "Or, evolution could be a lie."
No, evolution is a fact, but this article's suggestion is ludicrous.
mosesdapoet: "I know why you posted this.
You wanted to show a lot of FRs have pleanty of time on their hands this Independence Weekend."
;-)
In which case we'd need a gizzard to grind the grain as well.