The state government of Texas has set very strict rules in this area. Every single person, regardless of age, must acquire a license if they plan on hunting any bird or animal (this includes turtles and frogs). There are very few instances where this law may not be applicable such a when a coyote is attacking or when a fur-bearing animal is causing depredation on your land.
Special licenses include youth hunting, senior resident, lifetime resident, disabled veteran and resident active duty military. There are combo license packages too.
Get your license from an approved retailer or the Texas Outdoors website.