Biting the cage

[Emily<3]

So I have 2 girls, Aurora and Azalea, in a large dog kennel. They're happy, and have PLENTY of stuff to chew on. A few days ago Azalea started biting the metal bars on the cage and absolutely will not stop. Shes driving me insane. I open the door to see if maybe she wants to come out, but no she just moves to another spot. Any advice is appreciated as I feel like I'm going insane.

 

[Piggies&buns]

There can be many reasons why they do it - just because they want to, because they want something - hay, attention, more space, boredom.
All I can suggest is that you check that their cage really is big enough for them, that fhey have enough hay, perhaps try new chew toys (mine are only ever interested in something for a few days and then want something new so I keep several chew items and then rotate them in) and then try to wrap something around the bars.
If you search bar biting on this site, you will find many threads about it which may also help.