Due to lack of nutrition, and resulting hypothermia from the snowballs, you are probably right technically. Do note that some hay is so poor that there is virtually nothing for the bacteria to break down in the rumen which means there are no nutrients for the animal to absorb. Starvation is a slow way to die weather on snowballs or poor hay. Animals that die from starving on poor hay typically do so near the end of winter or early spring before or at green up.
Necropsy of animals in this condition shows a full rumen with no digestion taking place. The equivalent of feeding nothing, or rocks, or yes...snowballs.
