>>96827963
Morale checks are for when a side is losing and their spirit is broken, more on the level of killing one of the pack rather than just brandishing a torch.
But it's really up to you. You can even skip the check altogether and just make the animals act like you would imagine they'd act. If the wolves/giant rats are not particularly hungry, they might have no reason to attack in the first place, torch or no torch. And, if they're on the fence of whether they should fight or flee, the torch might be the tipping factor.