If a dinosaur were to had sat on its eggs... well, lets just say they wanted to hatch a baby, not an omelet. Rather than planting there immense bodies on their small eggs, they placed dead brush over them which would decay and warm the eggs. Also by doing this, they have the opportunity to do something else rather than sit on an egg all day.
The term is Brooding
Yes, a hen duck may sit on a nest with unfertilized eggs. Some hens exhibit broody behavior and will sit on eggs regardless of whether they are fertilized or not. However, the hen duck may eventually realize that the eggs are not viable and may abandon the nest.
for 21 or 22 days.
Wanting to sit on and hatch eggs.
No, absolutely not. Hens sit on their eggs until they hatch. They actually nestle their feathers above and around the eggs and keep them warm, but people say they are sitting or setting on their eggs.
all dinosaurs
Most, if not all, dinosaurs layed eggs.
They did not carry their eggs. Dinosaurs kept their eggs in nests just like modern birds and reptiles.
Dinosaurs, like many reptiles today, buried their eggs in warm soil or in piles of decomposing vegetation. Dinosurs did not sit on a nest like birds. The heat from the soil or decomposition incubated the eggs and the embryos matured. Some scientists think the mother dinosaur stayed close to the nest to protect the eggs or adjust the rotting vegetation to provide a correct temperature. At some point in their development the embryos broke out of the eggs, like chicks do, and started off on their own.
they layed eggs
Pretty much all dinosaurs lay eggs, so Spinosaurus likely did too.
All of them
All of them lay eggs.
Ankylosaurs were dinosaurs, and, like all dinosaurs, they would have laid eggs. Like other dinosaurs, their eggs would have had a hard shell made of calcium, like that of a bird, and not a soft, leathery shell like a turtle, snake, lizard, or crocodile egg.
Yes
Yes, all dinosaurs do
sit on the eggs