Hello and welcome to BYC!
Your place sounds like a wonderful place to be a chicken! LOL I am glad you are enjoying them so!
Generally a hen will not release another yolk until the one in the uterus has been laid. But sometimes, especially with young layers, a yolk can get released shortly after another one or while one is still getting a shell put on. Similar to double yolked eggs. Very high protein or over fed hens will release too many yolks as well. Genetics can determine how a hen releases yolks too.
Just make sure she eats plenty of layer feed. Laying can be taxing on a hen, especially with the need for calcium. So go lightly on the treats or goodies so she eats food that contains all she needs to lay these eggs. If a hen doesn't receive the proper vitamins or minerals in her diet, she steals it from her own system.
Great to have you aboard and enjoy your flock and BYC!! :-)