It's probably an advertising gimmick to persuade people that battery hens are better looked after than free range hens because they're protected from foxes..

      Probably right and a bald faced lie

I think the OP is just trying to fox us.

Are they Certified as Fox-Free.  And if so, where does the fee  end up.(Cracking up here.)

DEB

I haven't heard anymore about them. 

My thoughts were that the eggs were the ones the foxes didn't get.  Someone else said that hens who are frighten by foxes don.t lay eggs.

But who knows.

Yeh, I believe egg production lessens with stressed chooks.  

My daughter has some Goanna-free eggs.

DEB

"Goanna-free eggs"

It means they are not green.

Would you eat them
in a box?
Would you eat them
with a fox?

Not in a box.
Not with a fox.
Not in a house.
Not with a mouse.
I would not eat them here or there.
I would not eat them anywhere.
I would not eat green eggs and ham.
I do not like them, Sam-I-am.