Cheese Dragons are not actually alive. They are enchanted items of food that act almost identically to dragons. They have no need to eat, but they must “live” in humid environments or they will dry out and harden.

Silver Spoon, who thinks of herself as female, came to Kanaye by way of a Silver egg. Silver Spoon herself doesn't even know the whole story. Perhaps Kanaye generously gifted someone a Silver egg, and the giftee knew the only way to thank Kanaye properly was through a Cheese egg.

Or maybe it was something a bit more nefarious. Though Silver Spoon couldn't picture Kanaye sneaking into some poor noble's castle of dragons and thieve Silver Spoon's egg, leaving a Silver egg as payment. Doesn't mean it couldn't have happened.

No one even knows if it was a Silver egg her dragons bred or one that was abandoned, and unloved, until Kanaye came along and gave it purpose.

Whatever the reason, whatever the how or who, Kanaye paid a price to acquire Silver Spoon and Silver Spoon never let anyone forget it.