If you trust that a law will always be followed with the intent that it had when written, then all sorts of laws sound like a good idea at first.
If, on the other hand, you always assume that if a loophole for corruption exists, that someone wanting power will find it and exploit it, to the detriment of the subjects, then you are suspicious of laws which leave all the interpretive power in the hands of the government.
Considering that laws enacted with good intent have ALWAYS been corrupted and exploited, I think it is fair to assume that this one would be also. The goals of the nations of the UN are vastly different than the goals of the president of Bolivia (even though I think it will be bad law there too, it may take longer because the original intent runs through that country more than it does through the UN - many supporters in the UN already have goals to force veganism and socialism on the world as a whole).
Farm Subsidy and protection laws are a good example in the US. Enacted for the purpose of protecting small farmers from catastrophic weather or pest devastation, involving total losses of crops, and to maintain consistent supplies of key crops, the programs have been corrupted to do something entirely different than what they originally did.
Corrupt elected officers, desiring more power (which they felt would come from big business, and not from small farmers), combined with corrupt corporate farm lobbies, colluded to restrict the requirements for qualification for those subsidies, bit by bit. At this point in history, nobody BUT big corporate farms can qualify for farm subsidies or even claim for losses, because minimum loss levels and crop sizes have been raised to the point where small farms no longer qualify.
Laws will always be used by corrupt officials to gain more power.
I would not trust them to limit themselves when handing them legislation or regulation which gives them such far reaching power as "interpreting" the needs and desires of any entity which cannot speak for itself, especially when giving them that power gives them power over every aspect of life and every choice made by individuals on a daily basis.
No, government does not currently have that kind of power. In some areas they can tell me whether I can RAISE a chicken - not everywhere. They do not have the power now to tell me whether I can gather eggs from those chickens every morning.
The kind of law discussed here WOULD give them that kind of power. Once they determine that a chicken has the same rights I do - that is, the right to reproduce, the right to property, the right to decide for itself what it wants to do in its life - and once they decide that the government now has the "responsibility" to interpret what that chicken "wants", it is only a matter of time before someone on the appointed government board decides that maybe that chicken does not want me to take its eggs every day.
Either way, it sets up a situation where I have to ASK the government for PERMISSION to raise chickens, gather eggs, and butcher non-productive chickens. I must only feed them a diet approved by the government - after all, the chicken has a right to be fed what it wants to eat, and if the government must decide what the chicken wants, then the government must also dictate what is an appropriate chicken diet.
Currently, the Bolivian government states that butchering is allowed, and that the rights of animals do not supercede the rights of people - but they DO say they are EQUAL, and at some point, when they come into conflict, the rights of the chicken to live will be put ahead of the rights of the person to eat it (after all, if they are equal, the chicken has an equal right to eat the person in order to meet its own need for protein, does it not?). It is inevitable, because such laws always begin with the assumption that common sense will be applied at some point, but eventually people are appointed who desire power more than common sense.
The desire from corrupt people for power will always make it into something unintended at the outset. And this one has unlimited power to be corrupted, so inevitably, the lust for power will take it into the realm of the unthinkable.
People desiring power are MORE likely to seek public office, not less. So those who distrust the motives of the government in this kind of legal argument are wise to do so.
