re cribbing - what about chewing?

[Teresa Van Hove <tvanhove@uswest.net>]

Hi,

While we still on the subject - whats the story on
wood chewers?  My new 3 yr old is quite a beaver,
and has got the 4 yr old pony across the fence 
started chewing some too.  I haven't seen either
of them crib, though the 3 yr old might - she
does this odd gulp sometimes when I'm leading
her out of her pen to work her.  I've never had
to deal with this before.  The 3 yr old has no
reason to chew wood - she gets free choice hay
and is sharing a big dry lot with my gelding. 
The pony cant have free choice hay because she
gets too fat (need to find a kid to ride her 
hours and hours.) But does also have a decent
sized pen and a companion. I had those 2 together for
a few weeks when I first got the 3 yr old in
December and they are chewing the most on a 
post between their pens.  

Sorry this got so long - what are the recommendations?
A halt chew paint? cribbing collars?  Is this something
they'll grow out of?

Thanks, 
Teresa