I used to practice taxidermy myself. I probably would have taken it up as a profession, but I just didn’t feel like dealing with "dead things" all year long. Plus a taxidermist’s busiest time of the year is hunting season – when I’d rather be in the woods hunting.

Ok, so this is what you do my friend…

1) Take some cotton. Any kind of cotton balls or whatever. Like the kind the stuff they put in some asprin or vitamin bottles. Just some old discarded cotton or new cotton. Gently open the bird’s mouth and stuff the cotton into it’s mouth and possibly down it’s throat. Don’t overdo it. But do it.

2) Make CERTAIN you do not have blood on your hands. Then, smooth-out the feathers on the bird. Make a sort of "tube" out of some old newspapers. You don’t need a lot, but you need some.

First, wrap the bird gently in some paper towels. Take care to wrap the a bit of paper towel around the body and under the wings.

Next, place the bird head-first into the tube. Take another sheet of newspapers and wrap it around the body of the bird, and fold the wings over that. You basically want to cover the entire bird in newspaper.

The end result will be a pheasant that looks like it’s ready to be placed in King Tut’s tomb. Yes, a bit of a loosely fit newspaper mummy.

3) Place pheasant mummy into a sealed bag. Then place this gently into your freezer.

What are we trying to accomplish here?

By placing cotton inside the mouth/throat AND using paper towels and newspaper around the body, we are trying to make sure that any BLOOD from the bird will not soil/damage the plummage. The cotton and newspapers will prevent the blood from ruining the feathers. Blood on the feathers is very very hard to get out.

Also, by wrapping the bird in newspapers first, it gives it an extra layer of padding before it goes into the freezer. The bird will, of course, freeze solid. But with the newspapers in place, this will keep the body in a more "correct" position rather than "flattening-out" when it is placed in the freezer.

This all goes without saying – don’t place anything atop the bird while it’s in the freezer.

NOTE! Pheasant tail feathers are generally very long. Take extra care that you don’t break the tail feathers when removing the frozen bird from the freezer. Frozen animal parts are more brittle when handling.
References :
Proud Graduate of the Northwestern School of Taxidermy Arts
(In other words. I clipped a coupon out of the back of an Outdoor Life magazine and sent it in with a $14 money order.)

Most places use what is common for their area in the even some scamper away they wont have to worry about any problems with an invasive species. Hence again, just depends on where you are and what you prefer.
References :
work at a zoo