Is it possible for a chicken to lay more than one egg a day?

i have 8 hens and they lay 6-7 eggs every day.every 7-10 days i get 8,9 and a couple of times10 eggs in one day. i don`t know a lot about chickens but this seems odd to me. they are golden comets and are almost a year old.i feed them laying mash and pellets and scratch grains.also oyster shells and grit.how many eggs is normal per hen in good conditions?