It's a nasty habit that once is started is hard to break. I had one eating eggs and ended up culling her(she's in my freezer). I felt badly at first because I got her and others from my dad and to be honest,he did not feed them very well. After a month with me,they were very well fed,but this hen continued to eat eggs. Once I identified her(a long process in itself),I trimed her top beak back as much as I could without causing it to bleed. I then marked her with blue food coloring(she's one of several white leghorns) and waited. For several days all was well, but probably about a week later,the egg eating began again. You guessed it,her beak had grown out.