I'm still confused as to how you can legally get a ticket, and where any confusion can come from, for not having a HSC on your person when you are not actually hunting.
That is no different than the game warden giving you a ticket for having lead shot on you when you are dove hunting simply because it's during waterfowl season as well. If you are not in the act of actual violation of any law or statute, you cannot get a citation.
Once he showed the GW his license that was missing a buck tag gave proof that he had been hunting at some point. Having been hunting he had to show proof that he had HE. If he had said he didn't have a hunting license on him there would have been no proof that he had been hunting at any point therefore would not have gotten the ticket. He didn't have to be hunting at that particular time, probable cause came when he provided proof (hunting license missing a tag) that he did in fact hunt at some point this season. Texas law says you have to have HE to hunt if you were born after a certain date. Without a card to show HE, the GW has to assume he didn't have it when he hunted and killed the buck earlier in the season. Simple solution, provide proof of having taken HE and ticket dismissed.
I completely disagree. The OP didn't even have a firearm on his person, or in his truck. There is no act of hunting going on. He was filling his feeders. Whether or not he had any or all of his tags gone is completely irrelevant to the situation as described by the OP. He was not in the process of hunting - which is where the law begins and ends with respect to needing a license an HSC on your person (or your number printed on your license).
To make an analogy to your statement - this ticket would be like a LEO walking up to you in the parking lot of your local grocery store while you are loading your groceries in the back seat of your truck, then deciding that since you have a license and a truck, you have sped at some point in time and therefore decides to write you a ticket for speeding - speeding that he only assumes has happened but has zero proof of - while you are in the act of breaking exactly zero laws.
And if the OP had stated he didn't have his license on him, what is to stop the GW from making an assumption that the OP didn't have a license and was therefore poaching? Would you not agree that such a ticket would be illegal and unwarranted? How would that be any different than the assumption that the OP was hunting without all of the proper paperwork on him? Honestly, the two tickets principally would be exactly the same.
It sounds simple to just say "well, show up with your proof that you are innocent of this charge and everything will be dismissed". There are a couple of problems with that mentality:
1. The burden of proof is on the State, not the OP. It is up to the State (GW) to prove that the OP was actually violating a law. The OP was not violating any law at any time because he was filling his feeders during deer season. There is no law or statute that says you cannot fill feeders during deer season, and there is no law or statute that states that you must have a hunting license and your HSC on your person while you are filling feeders. Therefore by definition, the ticket was an illegal ticket that should never have been issued simply because there were zero laws or statues broken.
2. Simply going to court is not always as easy as it sounds. Doing so costs the OP time and money. Especially if the court in this case is not anywhere convenient to his residence. What if his lease was 8 hours away from his house? Now you are in a position of needing to use vacation days, or take no paid time off, to attend court for a ticket that was written when zero laws and statues were broken. And you know what? You don't get reimbursed for time off, fuel, food, etc. by the State when they do things like this. So you are still out money - and depending on your time availability and income, that could be a significant amount - regardless of whether the ticket was dismissed or not.