My terriers eating habits..

Question
My little dog is a cross terrier (Jack russel & Yorkshire Terrier) who i've had fom about 6 weks old is 9 months now and has started to bite and eat plastics and wood, especially the fece in my yard, also at night when i bring him in he is eating chunks out of my skirting board at the bottom of my walls ? I'm a bit worried about this can you tell me why he may be doing this ?
Also i am finding it really hard to train him to walk on a lead, he constantly seems to be choking and trying to run away from me, again is there something i should be doing to try and solve this or does it just take time ?
Any help and advice will be greatly appreciated.

Thankyou
Liam.  

Answer
With the breed that he is, he sounds like he is bored.  Sometimes dogs that are fine one minute seem to get bored and find things to do.  Most of the time it is BAD what they find.  You may want to start playing fetch with him.  Crate him when you can't watch him closely to stop him from chewing the base boards.  Give him large bones to chew.  Bleach Knckles you can find at redbarn.com work great.  

As far as the choking while walking.....He needs to be in an obedience class SOON.  They can help you fixing that problem.  

Hope that this helps.
Regards,
Tammy