The practice has survival advantages over laying few eggs. It is similar to swarm hatching. Where so many young hatch at once that there are not enough predators to eat them all. If there were enough predators then the predators would starve when there was not a swarm available. Consequently, predator numbers are unlikely to be great enough to consume all the members of a swarm.
It is not necessary, it is a true fact. There are different sized chickens so therefore there are different sized eggs that they lay.
fish that give no protection to their young lay large numbers of eggs
About 5.6 large eggs equal 8 small eggs
FROGS
9 large eggs equals 7.2 extra large.
To increase the chances of survival of the species
3 or 4 extra large eggs will about equal 5 large eggs.
there are energy constraints
To make more babies
At least 12 large eggs.
DEPENDS ON HOW LARGE THE EGGS ARE
Because so few survive. Either due to weather conditions or things that eat them.