One of our dogs has started chewing wood cumpulsively, and not just bark chips and branches from the garden but she's somehow managed to chew thro the parquet floor in the hallway, the stairs, antique wooden cabinet, the wooden hill on my brand new boots
...I was just wondering if anyone knows if she might be deficient in something?

Is she left alone all day? What breed is she?

Sounds as though she is deficient in attention, perhaps she needs more mental and physical exercise and some toys she CAN chew?

That's what I was thinking Tohme.  Dogs don't usually chew like that if they are just hungry.  Methinks the dog could be extremely bored!

I work from home, so they are always with me. The most they've been left alone is the odd 2-3hrs, which is very rarely.
She gets lots of attention and mental stimulation and as to toys a full box of them.

I vaguely remember reading somewhere about a dog that had an obsessive wood chewing disorder but was actualy later discovered that the dog was deficient in a certain vitamin or mineral but I can't remember which....

Does she do it whilst you are there then....in front of you?

what are you feeding her?