Droptine, I think your misinformed about whitetails. Rare do you ever find a 2.5 year old spike. I've hunted 26 bow seasons and 28 rifle seasons and I've never seen a 2.5 year old spike. Are you under the mindset that once a spike, always a spike? That's not so.
If you shoot her doe fawn, you wont notice a difference in numbers because she wouldnt have dropped a fawn for 2 seasons.
That statement tells me you think a doe is not bred at 1.5 years old. That couldn't further from the truth AND,
If you pop that mature do, you take 3 deer away for next year and 6 the following year.
your assuming she was bred to begin with which isn't always the case in an over populated doe herd plus, your assuming 6 the next year means she would have given birth to female offspring and not male twins who would have been bred but in your previous statement you said they didn't have offspring for two seasons. That's contradictory.