Regarding your first paragraph: most people would consider it unethical to murder someone for reasons of personal convenience, even if you donated to a ‘murder offset’ organization such as, I don’t know, let’s say police departments. MacAskill is saying that ‘animal murder’ offsets are unethical in this same way. Namely, you are committing an immoral act—killing an animal—then saving some other animals to ‘make up for it’. Climate offsets are different because the harm is never caused in this case.
Regarding your last paragraph: This is a nice example, but it will fail if your company might modulate the amount of food that it buys in the future based on how much gets eaten. For example, if they consistently have a bunch of leftover chicken, they might try to save some money by purchasing less chicken next time. If this is possible, then there is a reason not to eat the free chicken.
Regarding your first paragraph: most people would consider it unethical to murder someone for reasons of personal convenience, even if you donated to a ‘murder offset’ organization such as, I don’t know, let’s say police departments. MacAskill is saying that ‘animal murder’ offsets are unethical in this same way. Namely, you are committing an immoral act—killing an animal—then saving some other animals to ‘make up for it’. Climate offsets are different because the harm is never caused in this case.
Regarding your last paragraph: This is a nice example, but it will fail if your company might modulate the amount of food that it buys in the future based on how much gets eaten. For example, if they consistently have a bunch of leftover chicken, they might try to save some money by purchasing less chicken next time. If this is possible, then there is a reason not to eat the free chicken.