Hey! I did a little bit of snooping for you. I typed in "vegetarian fed hen eggs" to google and several websites came up. I chose to use the information from the Egg Nutrition Center because they are probably the most impartial source on the subject. Here's what they had to say:
"Vegetarian eggs and organic eggs are available from hens fed either feed free of animal by products or feed grown without pesticides, fungicides, herbicides, or commercial fertilizers, respectively."
http://www.enc-online.org/spec%20egg%20color.pdf
As far as how healthy they are, that's up for debate. You may get the contact info for the company and ask them. Hope this helps you some!
Allison