Use laser cutter to cut out a Facehugger pattern and a paint stencil.

You can download the DXF file from the links section (left side of main project page.)  Use only the outline to cut out Facehuggers.  Use all the inside holes to make a paint stencil.

Each (blank) Facehugger will get painted via the stencil to make it look better.

Cut out a few Facehuggers and paint each one via the paint stencil.

Glue a clay pigeon to the back of each Facehugger.

Now make the Egg.  I used Google image search to find a half-decent picture of an egg and had it printed in color at a print shop.

Glue it to some sturdy cardboard and then cut it out.

Attach the Egg to the front of the popper.  I used some caulking, but any sturdy, gap-filling glue should do the trick.

Attach the pigeon flipper attachment to the popper.  

The popper is a heavy steel plate that falls when shot.

That plate hits a lever, upon which is a clay pigeon.  It acts like a catapult and tosses it into the air.

The Facehugger goes where the clay pigeon would normally go.

Set it up in a suitable place, load up your shotgun, and so some live-fire ALIENS re-enacting!