Pipe organs may have as many as five "manuals", each of them almost the size of piano keyboard, and if would not be enough may even feature the feet keyboard. And my 88 key piano keyboard already covers the majority of the hear-able sound range, probably no more than 20 or about keys could be added to the sides, unless to play ultrasound for bats and whales.
Is it so that organ has multiple keys for the same note? How common is to play same note using different keys/pipes on the same piece of organ music?