The thing with ebay is unless you know the seller and ask questions, the eggs are like a gamble. Jumbo Brown eggs can be big, but not huge as those are generally double yolkers. They are bigger than pharaoh eggs. They are bigger birds after all. Now, if the birds just started laying, the eggs will be smaller, but it doesn't mean you won't get a big bird from it. Also, the older a hen is, the larger their eggs, therefore a huge egg could be a pharaoh...makes sense?
Egg Sizes Vary Greatly With A Hens Age... In The Beginning They Can Be Rather Small, As Time Goes On They Get Gradually Bigger Throughout The Birds Life, So Varying Sizes Can Be Quite Common And Misleading, Many Think Jumbo Bird = Big Egg/ Lil Bird = Lil Egg When In Fact I Have Seen Pharoah (small Sized Birds) Lay Eggs Way Bigger Than Their Larger Competition Simply Becuase The Small Hen Was A Feathered Dinosaur