Food: everyone's thinking about it, from the hungry Irish children to the exasperated English. Swift takes that tension and makes it the core of Irish identity in A Modest Proposal. It's an eat or get eaten world, and it's pretty clear where the children of beggars fall in that equation. And Swift makes it pretty clear that cannibalism has been going on for a while. Ireland is one big buffet for landlords draining resources and squandering money.
Parents. They just don't understand that the wrong move can seriously impact your social status. The poor kids in A Modest Proposal have it particularly bad: not only are their parents begging for alms, but they dress them in rags. Check out the "Society and Class" theme for more on why being poor can mean becoming dinner. Unfortunately, it only gets worse from here:
But my intention is very far from being confined to provide only for children of professed beggars; it is of a much greater extent, and shall take in the whole number of infants at a certain age who are born of parents in effect as little able to support them as those who demand our charity in the streets. (3)
So if your parents beg or don't make bank, you're doomed to be dinner. Thanks, Mom. If that distinction seems kind of arbitrary, you can thank Swift's overdeveloped sense of irony.
Animals are mentioned extensively in A Modest Proposal—see "Symbols" for a discussion of how they're used. The thing is, Swift's narrator isn't interested in comparing individual animals to the Irish people. He discusses cows, pigs, deer, and sheep, but only to show how they get treated as meat products. His exaggerated point is that they're poor and therefore not worthy of a personality.