The Mouldy Loaf

The farmer complained to the grocer about the blue-mouldy loaf which she had given his son for the tea. He said that it didn't go to waste because his wife used it as a poultice for her bad knee but that he objected strongly to the rusty nail that was in the loaf too. He didn't really mind the nail being in the loaf but it was in the heel of the loaf that they had given to the duck.
'Did it injure the intestine of any poor bird?1 asked the grocer.
'No. But Mary rode over the duck on her bike and I had to mend the puncture,' grumbled the farmer.