Walker is almost 9 months old and one of his ears just started to flop again. I was told they go through many changes throughout puppy hood. Teething seems to have some impact, so does their hormone level. I did what a few others here suggested: I shaved his ears, put tape around them (there are actually web sites on how to do this
) and voila, they both stayed up after only ONE night of tape! I wouldn't be too concerned at this point, but try the taping method.