The egg is an item from Freddi Fish 3: The Case of the Stolen Conch Shell.
The egg is found in Pierre the Tailor's shop where it is sitting on one of his hats on display. After Freddi Fish and Luther gives him the Blue-Tailed Joie Bird Feather, he gives them the egg for it was just too roly-poly. They later give the egg to the Blue-Tailed Joie Bird in exchange for one of the golden pipes. Once it was given, it hatches into a baby blue-tailed joie bird.