In what ways did Mollie standout from the other animals?

In Chapter Five, we see the advent of winter approaching, during which time, Mollie’s behavior becomes increasingly perturbed. She is late for work and feigns injury in order to shirk her duties. More seriously, Clover has spotted Mollie at the border of Foxwood, allowing Mr. Pilkington to stroke her nose and talk to her. Mollie denies the accusation, but her embarrassment confirms that she is lying. On a hunch, Clover goes to Mollie’s stall and finds a hidden stash of sugar and ribbons. Mollie disappears soon after. She is seen in a painted cart, gussied up and taking sugar from a man who appears to be some kind of manager. The other animals never mention her again.