I think it can technically happen - specifically maybe one early in the morning and then another late at night - but it's not normal. Should normally take about 26 hours between eggs.
One of my young hens used to lay two a day a few times a week, but she's an old lady now and barely lays at all, Sandie
Weeeeeeellll, I gotta tell ya- there are folks here who will tell ya its a physical impossibility, and the very next post will be about how someones "Henrrietta layed 2 eggs a day for days on end" . I say it is possible, but I dont think anyone could make it happen, or breed a chicken to lay 2 a day regularly. There seems to always be an exception to every rule when it comes to our birds! For myself, I have had it happen. I only had 1 hen and I got 2 eggs from her in one day- not one at 2 am and another at 11:30 at night, but an egg at 9 am and another around 8 pm. That only happened to me once though when she was young.