I have some great advice if you need to build a lightweight "catcher" for an egg that won't break the egg... We've successfully dropped eggs 5 stories into an 8 inch tall device made out of a styrofoam cup, a manilla folder, and some paper, string, and rubberband.
But, for what you're doing... 15 feet?! That's it???
A) Put egg in baggy; get rid of all air.
B) Cut top of a 2-liter bottle off (use this as a mold)
C) Get a can of GreatStuff (expanding foam used for insulating cracks)
D) keeping the egg centered, fill the 2 liter bottle with that foam.
E) The egg will possibly survive a drop from *ANY* height, due to terminal velocity. I believe we finally got such a device to fail after drop kicking it, spiking it on the ground, and finally, playing baseball with it.
Another suggestion: have a way to keep it suspended in the center of a dilatent fluid. (Look up what happens to corn starch and how you can mix it *just* right such that it's a viscous liquid, but instantly turns into a solid when placed under shearing forces.) When a capsule filled this way hits the ground, the medium surrounding the egg becomes as hard as concrete. The egg has no way to crack.