That Egg in Alien 3

Hi guys and gals, first post so forgive me if this has been debated here before but having just watched all 3 Alien movies back to back (you'll notice I said 3!!!), it still bothers me immensely where the hell that egg or eggs came from and how they got on the Sulaco at the start of the movie. I've heard numerous ideas from other fans such as the queen laying them in the drop ship or that Bishop brought them with him. The most surreal suggestion being that a team of Spec ops arrived on LV 426 before the marines and obtained the eggs and then placed them on board while everyone was in cryo!!!!! I wish the writers could just explain this as it has a huge bearing on the overall franchise and as it stands it's a bit of a plot hole! Anyone any thoughts? again, I'm new so sorry if this has been debated before.