rotten eggs are horrible! and I noticed that no one else has answered you yet, so before I leave, I just thought I would try to lend some helpful(hopefully) info for you.
First of all, don't throw out those eggs yet! Just because one was bad, doesn't really mean the rest are. How many eggs do you have total?Has your temp. and hum. been steady and in the correct range? I know nothing about pheasants, let alone pheasant eggs, but I will try my best to help you anyway.
How many days does it usually take for pheasant eggs to hatch?
I would first of all candle the eggs to see if some are still alive. If they are not alive and/or are rotten, you nay see that the egg looks watery, has no healthy-looking red veins, is not moving, etc. the rotten eggs may smell bad if you smell them(like rotten egg) and if any are leaking, TAKE THEM OUT BEFORE THEY EXPLODE!
It is pretty highly possible that if they are 2 days overdue, they may all not be good. But please make sure before you throw them all out; I've heard so many stories on here about how someone thought an egg was bad and there was really a live chick in it.
Good luck!
