I have a regular 'double yolker' from a huge hen. Heaviest 124g......ouch!
I did incubate one a few years back (we live out in the sticks and have 5 roosters). Initially two embryos developed,but both died before hatching. If it is just a large single-yolked egg then the chick comes out slightly bigger.....the embryo was regular sized,but they had a lot of food from the big yolk. They go on to form regular-sized chickens.
Some folk have successfully hatched 'twins', but they need help out of the shell.....there are a few YouTube videos if you are interested.
I don't have a rooster, so my eggs will never make any chicks. It would be fun to hatch some eggs, but, here in the city they frown upon keeping roosters.