Hello,
When they are kept alone, they can still develop infertile eggs, yes. Some say that they are less prone to developing infertile eggs if they do not see other dragons because their hormones are not stimulated cause ovulation.
However, they can still have egg binding problems with infertile eggs because there is always a risk of low calcium, an irregularly shaped egg that is hard to pass, or other genetic or physical problems.
Tracie