Lucy tears apart the chair in the Mertzes' living room and feathers fly all over. Later, as Lucy and Ethel sit on the couch in Lucy's apartment, an errant feather floats own to Lucy's left.
There's a window on the stage right wall of the Mertzs' apartment that is not there in any other episode. Because Fred is such a cheapskate it isn't likely that he would have installed a window, then removed it.