Questions Response: The Norcross argument

Please read Alastair Norcross: "Puppies, Pigs, and People: Eating Meat and Marginal Cases" and answer prompt a and b.
Theres no need to compose this as an essay, instead just answer the question.
So, in "Puppies, Pigs, and People: Eating Meat and Marginal Cases", Alastair Norcross argues that the problem of marginal cases is a serious problem we must confront. In effect, the problem of marginal cases says the following: Whatever kind and level of rationality that is required for full moral status that excludes animals, there will be some humans who fail to have that status. These "marginal cases" will include infants and small children, temporarily cognitively-impaired adults, and permanently cognitively-impaired adults. If we claim that differences in rationality means that animals do not have full moral standing, we have to say that the same is true of infants, and the cognitively impaired. Norcross argues that what these marginal cases show is that if a subject fails to be morally evaluable, it does not mean that we can treat him or her any way we choose. The reason why is that even if such subjects cannot reason, they can still suffer. (Notice how this puts Norcross squarely within a Utilitarian and not a Kantian camp.)
(a) Do you think Norcross's argument holds up? Why or why not?
(b) If Norcross's argument holds up, is there any way of supporting a large meat-eating culture that does not cause large amounts of suffering to animals? (Assume here that free-range and cage-less farming cause less suffering than factory farms, but they do not eliminate it completely.)