House breaking a 1 yr old dog

Question
I have a 1 yr old minature dashaund.  We got him when he was only 5 weeks old.  We have also crated him and he has always done great not pottying in his crate.  We have worked with him on the house breaking, but sometimes he still poops in the house and I do not know what else to do.  Now, just lately, he has started pooping in his crate.  What in the world has led him to start doing this.  Nothing about his routine, eating habits, etc. have changed.  His crate is not new and not too big for him.  I am at a loss about why he has started doing this and why I have never been able to completely get him trained.  HELP!

Answer
Usually, if a dog is still having house training issues at this age, it's because something went wrong in the training process.  If he was scolded for mistakes, for example, he may not have learned "no pooping in the house", he may just have learned "it's scary to poop in front of humans - I'd better hide that poop in my crate/the living room/behind that door, etc."  The key to fixing any house training problem, as long as the dog has no medical issues, or no recent life changes, is usually all about more diligent supervision.  I sometimes suggest that owners not scold, keep the dog tethered to their waist (Google on "buddy leash"), and monitor all the dog's activity while he is outside the crate.  That way, you don't even have to allow him access to the crate until he has defecated outdoors:-)