These two phrases mean basically the same thing. Alternate translation: "They are unjust to the poor and needy among my people" (See: [[rc://en/ta/man/translate/figs-parallelism]])
Isaiah compares orphans to animals that other animals hunt and eat. This emphasizes that orphans are powerless and judges can easily harm them. Alternate translation: "harm children who do not have parents like an animal that goes after its prey" (See: [[rc://en/ta/man/translate/figs-metaphor]])