In my opinion, "squalid" sounds strange for people. Because it's a negative word for an environment, it would also sound negative for a person, and especially for a child. There is poetic license but I can't imagine it ever sounding good for a child. If you posted the whole line, then perhaps some other words could come to mind. Jerry's options sound good.

How about dirty, filthy, slovenly, unclean And yes, it does sound out of place to describe a person as squalid to my ear. That's my .02 worth. I agree with Sara, the meaning is clear.

It wouldn't be unprecedented. A Google search of Project Gutenberg turns up: "I saw a livid face, the face as of a man long drowned,--bloated, bleached, seaweed tangled in its dripping hair; and at her feet lay a form as of a corpse; and beside the corpse there cowered a child, a miserable, squalid child, with famine in its cheeks and fear in its eyes."--Edward Bulwer-Lytton, "The Haunted and the Haunters." Of course someone is going to wisecrack about Bulwer-Lytton, because of the Bulwer-Lytton Fiction Contest; for some reason, one of his opening lines, "It was a dark and stormy night..." is thought to be horrible (I don't think it is) and has become a kind of joke. A Google Books search turns up many examples of the phrase "squalid child." Most of them are from the nineteenth century, but "squalid" itself is a somewhat old-fashioned word. An impressive number of them are anthologies containing "The Haunted and the Hunters" so it must be considered a good story.

Yes i agree with both Sara and Jerry, it sounded a bit odd. Having read the phrase a couple times I think it sounds better now. I think filthy or grimy could be used here.

It does sound odd, yes, but I think people will understand what you mean. Plus-- it's poetry, which is meant to be creative and different.