Texas Agriculture Code - AGRIC § 146.005. Permits to Transport Animals

(a) A person who drives a vehicle, including a truck or an automobile, containing livestock, domestic fowl, slaughtered livestock or domestic fowl, or butchered portions of livestock or domestic fowl on a highway, public street, or thoroughfare or on property owned or leased by a person other than the driver shall obtain a permit authorizing the movement.

(b) A permit must be signed by the owner or caretaker of the shipment or by the owner or person in control of the land from which the driver began movement. In addition, the permit must state the following information:

(c) On demand of a peace officer or any other person, the driver shall exhibit the permit required by this section or shall provide a signed, written statement containing all of the information required for a permit under this section.

(d) Failure or refusal of a driver to exhibit a permit or provide a statement in accordance with this section is probable cause for a search of the vehicle to determine if it contains stolen property and for detaining the shipment a reasonable length of time to make that determination.