No railroad company, in transporting animals, shall permit them to be confined in cars more than twenty-eight consecutive hours, except when transported in cars in which they have proper food, water, space and opportunity for rest, without unloading them for food, water and rest, for at least five consecutive hours, unless prevented by storm or other accidental cause; and, in estimating such confinement, the time during which the animals have been confined, without such rest, on connecting roads from which they are received, shall be included. Animals so unloaded shall be properly fed, watered and sheltered during such rest by the owner or person having their custody or, on his neglect, by the railroad company transporting them, at his expense; and such company shall, in such case, have a lien upon such animals for food, care and custody furnished and shall not be liable for any detention of them for such purpose. Any such company or the owner or custodian of such animals, who does not comply with the provisions of this section, shall be fined not more than five hundred dollars. The knowledge and acts of agents of, and of persons employed by, such company, in regard to animals transported, owned or employed by it or in its custody, shall be held to be its acts and knowledge.