Quote 25
The number of souls in this kingdom being usually reckoned one million and a half, of these I calculate there may be about two hundred thousand couple whose wives are breeders, from which number I subtract thirty thousand couple who are able to maintain children, although I apprehend there cannot be as many under the present distresses of the kingdom. (6)
Get ready for a bunch of numbers. This was actually one of Swift's big gripes: people were viewed as numbers and not… well, people.
Quote 26
I am assured by our merchants that a boy or a girl before twelve years old is no saleable commodity […] which cannot turn account either to the parents or the kingdom, the charge of nutriment and rags having been at least four times that value. (8)
Pre-teens: what are they good for? The narrator later contradicts himself to make a halfhearted argument about using them to replace deer meat.
Quote 27
I do therefore humbly offer it to public consideration that of the hundred and twenty thousand children already computed, twenty thousand may be reserved for breed, whereof only one fourth part to be males, which is more than we allow to sheep, black cattle, or swine. (11)
The level of detail is meant to be shocking. You don't suggest that kids can be raised for food without going all the way with the metaphor.