No PM in box, Let just say "or something". I am educated in environmental sciences and try to keep up on the literature.
I find it hard to imagine it's malnourished having lived in that jungle out there. There is food everywere.
That is a common misconception. All forage is not equal and not all plants are forage to elk.
This actually another very complicated subject so I will be very brief. Most plants have lignin in them or cellulose. Some have very little and others a lot. Pick up a piece of grass and than grab a piece of salal. Feel the difference? Most plants especially shrubs have secondary defensive compounds that are toxic or digestion inhibitors to animals. These things affect how efficiently an animal can digest it. Next time you eat an orange take a piece of the peel and fold it and squeeze it next to a lit lighter. You will see a little flash. That is a secondary compound that makes the peel not taste so good. Forage is often measured in digestibility. Basically what percentage is digestible. This can then be related to digestible energy. Basically the lower the digestible energy the poorer quality the forage is. Does not mean that the poor forage does not benefit them in some way but they need good forage to survive. Try eating only ice burg lettuce for a week or two. What is good depends on the species and the niche it occupies. So I am staying on elk. Some plants are only available at certain time of the year while others that are present year round. The year round species may be lower in digestible energy in the winter and higher in the spring. So when you see all the green you have to ask what is functionally available. Think of it this way. You harvest an elk, have no way of storing it, so you start eating it. Well a lot will go bad and thus is not functionally available to you as potential energy. Also you can not survive on elk alone. Yeah, I know it sucks. Like you, elk need a variety of plants to get all the necessary nutrients.
Elk can not adjust the amount of forage eaten by the quality. In other words increase intake to get more energy. They can only eat so much and then they have to ruminate. They can only ruminate so long and then the forage passes. The digestibility of the forage will equate to how much the forage will benefit them. So if the have to fill up on poor forage they will expend more energy digesting it then they will receive from it.
Now to confuse things. Their ability to digest/ consume food actually declines during the winter and have adapted to catabalize body tissue during the winter. So for them to lose 10% body mass over winter is perfectly normal and will not affect them one bit.
Well that should get you thinking. Feel free to ask some more questions.
One last thing. We hunters really need to understand more the importance of forage to the species we pursue. To often we blame predators, other hunters, or bad management on low numbers. When the greatest limiting factor is food. A cow elk can not come into estrus if she is not a certain nutritional level. This is one reason why we see some cows get bred later. simply put they need another month to get up to the right body condition. Also one reason why you do not see one calf for every cow.
Here is an interesting link:
http://www.cnr.uidaho.edu/range556/Appl_BEHAVE/projects/toxins-wildlife.htm