
I don't have kennels myself, but my friend runs kennels and has said to me in the past that having wooden kennels or plastic are dangerous not only for the chewing side of things but also germs can soak into the wood and they are harder to keep clean.
She has metal kennels and swears by them, for cleaning and keeping the risk of germs at bay.
When I win the lottery! I am going to have a HUGE house with some kennels, communal ones like the Guide dogs for the blind have, tiled flooring (non slip might i add!) with good quality metal kennels. AHHHHHHHH I can only dream,,,,,,,,,,, :P