Little Donkey With Errant Ears

I can't see a donkey without reciting GK Chesterton's poem to myself.

"With monstrous head and sickening cry and ears like errant wings." Except that this donkey, which I saw enjoying a meal of lovely fresh hay at sunset in the Lee Valley Park this afternoon, hasn't got wing-like ears. This Jenny is certainly a parody but not of the devil. I think she is pregnant. Wonder if her offspring will be lop-eared?