Hyenas are large wild animals that look like dogs and eat dead animals. Their loud cry sounds like a person laughing. (See: [[rc://en/ta/man/jit/translate-unknown]])
These two phrases mean basically the same thing. "Her time" and "her days" both refer to the time that God has chosen for Babylon to be destroyed. This can be stated in active form. Alternate translation: "The time that all of this will happen to the people of Babylon is near, and nothing will stop it" (See: [[rc://en/ta/man/jit/figs-parallelism]] and [[rc://en/ta/man/jit/figs-activepassive]])