Orpingtons are lovely chickens, and I'm so sad that you have lost Olive, Barbara. She sounds like quite a character.
There's quite a lot of evidence that chickens do feel the loss of one of their flock. I've certainly seen it with my own. Poor Ruby.
Allow yourself time to grieve and feel Olive's loss. Whatever anyone else may think, losing a loved chicken is just as bad as losing any other pet. Even if we do know they've been ill, it's never easy.