Tex. Tax Code § 23.521

(a) The Parks and Wildlife Department, with the assistance of the comptroller, shall develop standards for determining whether land qualifies under Section 23.51(7) for appraisal under this subchapter. The comptroller by rule shall adopt the standards developed by the Parks and Wildlife Department and distribute those rules to each appraisal district. On request of the Parks and Wildlife Department, the Texas Agricultural Extension Service shall assist the department in developing the standards.

(b) The standards adopted under Subsection (a) may require that a tract of land be a specified minimum size to qualify under Section 23.51(7)(A) for appraisal under this subchapter, taking into consideration one or more of the following factors:

(1) the activities listed in Section 23.51(7)(A);

(2) the type of indigenous wild animal population the land is being used to propagate;

(3) the region in this state in which the land is located; and

(4) any other factor the Parks and Wildlife Department determines is relevant.

(c) The standards adopted under Subsection (a) may include specifications for a written management plan to be developed by a landowner if the landowner receives a request for a written management plan from a chief appraiser as part of a request for additional information under Section 23.57.

(d) In determining whether land qualifies under Section 23.51(7) for appraisal under this subchapter, the chief appraiser and the appraisal review board shall apply the standards adopted under Subsection (a) and, to the extent they do not conflict with those standards, the appraisal manuals developed and distributed under Section 23.52(d).