Heeler / terrier mix for homestead

We have four dogs out here in rural Texas. It takes a steady presence to keep the wild critters at bay. We have coyotes, puma, pigs, rats, mice, foxes, bobcats, hawks, snakes, coons, armadillos and a few possums.

We got our first two dogs from a neighbor when a Blue Heeler accidentally mated with their Rat Terrier / Jack Russell cross.  The result is a Heeler/Terrier cross that is spectacularly helpful for the homestead. They are incredibly protective and energetic.
. They don't bother chickens. We introduced them to a rooster when they were pups (he pecked and chased them).
. They absolutely hate large birds, which is what caused our only chicken losses.  They chase every flying thing to the fence lines.
. They sit at night and listen to the coyotes, but have enough sense to not go outside our zone 2 fence to confront them.
. We have seen one leap over an electric fence to grab a rat that emerged from compost we were turning. He had it in a second, and they took turns biting it to death.
. They bring dead coons back occasionally. Coons are fearsome fighters.
. They have enough sense also to not confront bobcats, which are deadly.
. They are not too big, only about 25 lbs, but they do eat a lot being so active.
. They are great watchdogs. Nobody but nobody comes hear here unchallenged.
. They herd our cattle on demand. How they don't get kicked is a miracle. Very quick reflexes.

Some might find this breed mix too aggressive. We took them in HEB in a shopping cart several times when they were young to socialize them. They have not bitten anyone, but they have nipped at a few folks' heels. This is typical Heeler trait and how they herd cattle.  So these two are not excessively aggressive.

However we picked up a full Red Heeler about 7 months ago, and she is showing signs of being very protective. So I'm training her as a truck dog to accompany any of our womenfolk who have to drive alone. She is much more quiet and watchful, but explosive in defense. This one I suspect we'll have to put inside when the creepy Amazon drivers come.  She has also, at a young age, subjugated ALL the other dogs except the dominant male Heeler/Terrier.  The forth dog is bigger than her, a Shepherd/Heeler cross and he has lower energy in general.