What Thai restaurants post on their door to signify a temporary closure of the restaurant. If the manager is out, hood translates to 'head' thus giving more definition to the concept itself. Additionally, the 'it' is a philosophical reference to the state the 'hood' is in. To fully comprehend such sign, read it as "The HEAD IS not working"
Manager/owner is out of town on business for a few days and there is nobody to take over the job. Restaurant will post sign reading: The hood it not working"