Rodent Related Isues

[Gp G.]

Tenant says rodent issue she noticed. Looks like rodents are chewing some books and some gifts. Is the rodent issue is tenant responsibility or landlord responsibility? I spoke to one big company and they are saying thousands of dollars to fix it based on their initial free estimate visit to close all the holes etc. around the property and to put cages to catch existing ones in the property. Please advise.
Thanks,