Boxer abnormally skinny and using bathroom in crate!!!!

Question
I have female fawn boxer who is almost 5 mos. old. We first got her she did fine in the crate over night and during the day when we were at work. The only time we put her in the crate now is when we are gone, she sleeps beside our bed at night. It doesn't matter if we are gone for 1/2 hour or 8 hrs. she will pee and poop in her crate. Also I have recently noticed she is getting skinnier. Her ribs, spine and even bones in her tail are showing. We feed her approx. 1 1/2 - 2 c. of Purina One puppy food a day. We have tried to feed her more but she then poops everywhere. I have also recently noticed her skin and fur have an awkward smell. I need help, please. What advice do you have?

Answer
There are probably a few things going on here.  One is that she seems to be developing some separation anxiety - hence the urination/defecation in the crate.  Here are some links on separation anxiety, and on canine learning/fear periods (as she's approaching puberty and a fear period, as well):
http://www.inch.com/~dogs/separationanxiety.html
http://www.perfectpaws.com/sa.html
http://www.clickersolutions.com/articles/2002/sa.htm
http://www.doglistener.co.uk/puppies/criticalperiods.shtml
http://www.weimclubamerica.org/yourweim/development2.html

As far as her weight, Boxer puppies do go through growth stages where they look like walking skeletons.  This should not last more than a week or so.  That said, 1.5-2 cups of Purina ONE sounds like not very much food - I fed that at one time and was feeding about 4-5 cups per day.  If she's having lots of stool on that food, you might consider switching to a higher quality food (higher quality = fewer fillers = less waste).  Solid Gold, Timberwolf, Innova, Wellness, Blue Buffalo are all brands which are higher quality and fairly easy to find (there are others, as well) - a good site for evaluating kibbles is www.dogfoodanalysis.com

Good luck!