Whenever any person having animals in his possession, or keeping animals within a place wherein infectious or contagious disease exists, posts a notice at the entrance of a building or enclosed place in which such animals are kept, forbidding persons to enter that building or place without his permission, and any person, not having the right of entrance into the said building or place, knowingly enters into the same, or any part thereof, in violation of the notice, the person so entering shall for each such offense be liable to a fine of not exceeding $20.