For one thing, I severely doubt wild game would have been plentiful enough to meet more than a very small fraction of the nutritional needs of a Roman army. There is not enough wild game in the US for example to feed more than a quite small fraction of the survivors of a nuclear war according to a calculation I saw -- and the survivors in that scenario have the luxury of remaining spread out over the countryside and of ranging around without incurring the risk of running into a superior number of enemy soldiers.
We're talking about soldiers stalking the wilderness of Pliny the Elder's past, not the present-day United States where game populations have declined dramatically. Furthermore, the population figures are way out of whack as well. The city of Rome in early imperial times was at best half a million people. Pliny the Elder's hometown of Como in northern Italy might have housed up to 10,000. An army drawn from that city would have been a few thousand soldiers at maximum.
Armies in ancient times did NOT have the highly sophisticated logistics networks that we have in the modern day. Subsisting on hunting and gathering was a major part of the soldier's life [1].
2000 years ago in the regions where the Roman army operated, animal husbandry was already an established way of life for 5000 years or even (in some spots like Asia Minor) a lot longer than that, and the overwhelming majority of the mammalian biomass was in the form of domesticated animals, not wildlife. The land that was not under cultivation was either quite hilly or had something wrong with it that make it bad for supporting wildlife just like it was bad for supporting agriculture.
The page you linked does not mention "hunt" except in 2 of the comments (and one comment is about hunting enemy soldiers). Do you claim that the other comment that mentions "hunt" supports your position?
If not, please quote the passage on the page that supports your position.
Foraging for soldiers included plundering and pillaging the local population. They could also just have easily hunted the local villagers' livestock as a source of meat which they could then salt and preserve for food on the march.
The article I listed explained in detail how Roman soldiers carried out the full process of turning grain into flour and then baking bread in their encampments. You don't think they could have managed the slaughtering of livestock?
But besides that, there were plenty of forests around (which they used to gather firewood, as mentioned in the article). Those forests absolutely would have contained deer and other game they could hunt and preserve.
In a previous comment, you wrote about Roman soldiers "hunting any game they came across". "Game" means wild animals.
Of course they stole and ate any livestock they could get unless they were passing through the territory of an ally, in which case the commander probably has warned the men that any man caught pillaging would be executed, but in compensation, the commander had probably purchased livestock and other food from the ally to be distributed to the men.
I did some more research. The Romans actually had dedicated hunting units attached to their armies, called venatores. They hunted wild game for food and also captured animals to return to the city for entertainment (venationes) and public executions (damnatio ad bestias).
So not only did they hunt, they made it a formal part of their military, not merely an opportunistic food source.
I have to say, I don't appreciate that you would take such an obstinate stance without doing any research of your own. It's intellectually lazy.
For one thing, I severely doubt wild game would have been plentiful enough to meet more than a very small fraction of the nutritional needs of a Roman army. There is not enough wild game in the US for example to feed more than a quite small fraction of the survivors of a nuclear war according to a calculation I saw -- and the survivors in that scenario have the luxury of remaining spread out over the countryside and of ranging around without incurring the risk of running into a superior number of enemy soldiers.