The Australian army has had enough difficulty dealing with emus already. Dinosaurs would absolutely wipe them out.

On a more serious note, are egg sizes proportional to the size of the animal, or does the curve flatten after a certain size? I can't imagine an adult T-Rex dropping eggs that are 90cm across, for example, without either breaking them or making the shell impractically thick.

there is a maximum viable egg size, which is about as big as an ostrich egg, due to the square-cube law. Eggs need to be semi-breathable, but as volume increases cubically, surface area increases only quadratically, but surface area is needed for breathability.

So huge dinosaurs had eggs that weren't much bigger than ostrich eggs, containing relatively tiny offspring. Maybe they would have been very cute. Or not, since baby birds often aren't that cute.

Since eggs had to be small, many dinosaurs utilized r-selection, like sea turtles for example, producing large numbers of eggs that only a tiny percent of which would survive to adulthood. This may also be why there were such ferociously efficient superpredator dinosaurs, because there were large numbers of relatively helpless juvenile dinosaurs scampering around to be preyed upon.