hens going broody then going of the nest

[bb orpington]

i have 1 blue orpington that has gone broody then gone off her eggs and behaved like all my other orpingtons she has been out there for a long time. so i was hoping someone could give me some info about why

 

[Pork Pie]

I would imagine that she is new to being broody? It can be confusing for first timers. I prefer to let my alpha hen sit - she's done it 4 times this year and she knows what she is doing - i usually break the broodiness when i don't want to set eggs.
CT