Chewing and messing in the house

Question
Hi I have a 9 month old labrador x mastiff, which I've had since he was 12 weeks old. 2 months ago we also got a boxer who is now around a year old. The labrador x was fully house trained, never chewed on anything, the only problem we have with him is that he pulls on the lead. The boxer seems to be the main problem, since we have had her she chews on things overnight and sometimes when left alone (even for a short period of time like school runs), we've gotten very good at keeping things out of her reach, however she can jump up on the sides and will end up getting something else regardless of what it is or breaking something. we went through a period where she seemed to be improving but we seem to have a set back - just this morning I came downstairs and she has chewed my daughters lunchbox (again) and messed in the house. she never messes in the house during the day it's just overnight but I don't know how to get her to stop, during the day she will go to the back door but overnight she doesn't even do it anywhere near the back door which says to me that she hasn't even attempted to try to get out, but because she is doing this it is now making the labrador do it too. they both get exercised at 6 in the morning and in the evening, they are not left alone or unattended for very long periods, we let them out every night before we go to bed (which for my husband is ususally around midnight every night) and I get up at 5 am so they don't even get left for very long overnight and overnight they still have access to us, they sleep in the hallway outside of our bedroom. We've tried everything we can think of but are slowly running out of ideas. If you are able to give some advice it would be very much appreciated. Thank you

Answer
Hello, Zaidah!

Check out this blog post for your Boxer's chewing problems:  http://blog.gizmo2wizmo.com/2009/03/16/how-to-stop-your-chewing-dog.aspx

For peeing in the house at night you may want to try keeping her in a dog crate at night, at least until she is well past the habit of peeing in the house at night.

Good luck!