The following post compares human figures from 5 different manuscripts and printed books from roughly the same era, I have found only one hint of having an ear in a single image there: You are not allowed to view links. Register or Login to view.
Looks like ears were mostly hidden by hair or headwear at the time and it looks like not drawing ears was a common practice.
As a side note, I find it hard to imagine why a deaf artist in particular wouldn't draw ears. When ears are exposed they are a very visible part of anatomy, whether one can hear or not. To me it sounds a bit like saying artists won't draw eyebrows because they don't use them personally for anything.
Looks like ears were mostly hidden by hair or headwear at the time and it looks like not drawing ears was a common practice.
As a side note, I find it hard to imagine why a deaf artist in particular wouldn't draw ears. When ears are exposed they are a very visible part of anatomy, whether one can hear or not. To me it sounds a bit like saying artists won't draw eyebrows because they don't use them personally for anything.