I'm no expert on this, so hopefully someone chimes in, but as far as I can see, there is no dragon for 28 hours. So if you are looking at the timer (not the gold cost), then I think you might have a case of your breeding time being doubled. It is strange that yours says 28 hours because it usually displays 2 days for that amount of time. I am curious what your gold cost is and if you updated your game recently... Regardless, I am assuming you have a Eagle and your breeding time was doubled unless there is a dragon I don't know about.