Can Vegans Make Broth from Dead Vagrants?

Introduction

For the last half-year or so I've been thinking about the ethics of eating animal byproducts. Here's what I mean: Let's suppose that you believe that it's unethical to eat factory farmed meat and dairy (or any meat or dairy--nothing important to my argument hangs on this).  As someone who lives according to your considered ethical judgments, is it permissible for you to eat by-products from the meat and dairy industry that would otherwise be thrown out?

Before continuing I should make one thing clear: These arguments only work so long as the byproducts would (a) otherwise be thrown out and (b) do not contribute to the demand for the primary product. Also I'll need to assume that current conditions persist, that is, the majority of the population isn't vegetarian and there is significant demand for the primary products.

Case 1: Whey

Let me give you some examples of by-products. Whey is a waste by-product of cheese-making and greek yogurt production. Its disposal is actually a significant environmental problem since millions of tons are produced every day (in the US alone) [see: cheese, greek yogurt]. In a whey (sorry, couldn't help myself)  eating the waste product is a net environmental good. If left unconsumed it would otherwise have to be treated in an industrial digester which is an energy intensive process. Also, simply dumping it into nearby water sources contaminates the water and kills all the flora and fauna and so it cannot be done. 

There are two basic arguments for why it might be morally permissible for a vegetarian or vegan to eat whey products.  First of all, there's so much excess whey from primary dairy processes that your actions don't perpetuate or generate additional demand on primary products (i.e., milk/cheese). That is, consuming whey doesn't cause milk producers to produce more milk or cheese. Second, consuming whey actually minimizes the environmental impact of the dairy industry. Instead of excess whey contaminating the environment, we eat it.

There is a possible counter-argument. By consuming whey we create a market for it which makes it cheaper for the dairy industry to get rid of it. Currently they have to pay people to take it (e.g., farmers who use it fields or to feed animals, and whey product producers).  If the cost of disposal is reduced, the price of primary products also comes down (because total production cost is lower since disposal cost went down). If the cost of primary products comes down then standard economic theory predicts demand for primary products increases.

I'm not quite sure if this argument works. I'd need to consult with an economist to know for sure but here's one possible way to reply. Suppose we agree with the counter argument that the cost of production for cheese and milk will come down thereby increasing demand. Baaaaat! If demand for milk/cheese increases so will the quantity of byproduct (whey) produced and since the vegetarians are already eating as much as they can, the cost of disposing of this extra waste (from producing even more milk and cheese) will also rise perhaps causing the price of primary products to settle back around where they started. I'm no economist but anywhey, lets look at another case...

Another thing to consider is that we might already be at peak whey consumption. Also, the amount of whey that vegetarians and vegans might consume (that don't already consume it) could be negligible in terms of how much excess there is. Recall that there are several million tons produced err' day.

Case 2: Animal Carcasses 

I came up with this next case as a result of motivated reasoning. It's freakin' cold in Ohio and I've been making a lot of legume soups and stews. What I'd really like is to use a chicken broth but being a committed (albeit imperfect) vegetarian, I don't buy chicken or chicken bouillon. 

But I was thinking... Suppose an omnivore friend had roast chicken for dinner and was about to throw away the carcass. Would it violate vegetarian or vegan ethics to use the carcass for a broth? I guess what I'm really asking is if there is something intrinsically bad about consuming animal products or is it only bad because of how they got on our plate? 

I think the reasonable answer is that eating meat isn't intrinsically bad, it's only bad if certain ethical conditions were violated in raising and/or killing the animal. I doubt there's anything morally wrong with eating roadkill or eating an animal that died of natural causes. It might not be a very appetizing thought, but it's hard to see why a vegetarian or vegan would say it's wrong.

The only possible argument I could think of is if (a) you think it's just as wrong to eat an animal as it is to eat a human and (b) you think it's intrinsically morally wrong to eat humans. Suppose we agree with (a). Is (b) likely?  I don't think so. We can all probably agree that it's wrong to kill someone to eat them but if someone died of natural causes and you were starving, would it be wrong to use them for soup? Probably not. You might have an aversion to it but it's hard to see why it would be morally wrong. 

Of course, the case of my friend's chicken carcass is a bit more complicated than eating roadkill.  The vegetarian/vegan will be ethically opposed to how the chicken got to the plate (especially) if the chicken was conventionally raised and killed. That said, the vegetarian/vegan's actions don't generate demand for the primary product (i.e., don't support or perpetuate the meat industry) and the byproduct is going to be thrown away anywhey.  In such a case, is there any harm or is there a wrong?

I'm curious what my vegetarian/vegan friends think.  By the way, I'm headed down to the morgue to get some bones to make both. Let me know if you'd like me to get some for you while I'm there.