Please help ( and I will post this to the other Aussie thread ).    I might be worrying needlessly, but have not found any answers to my questions on any links, on here at BYC, or by Googling all kinds of things about shell-less eggs. 
 
My little Aussie Araucana ( Mindy ) .... has had a couple of bouts of broodiness recently.   Got her over those within a few days, she quit laying for a week or so and then produced an egg almost each day beautifully.   Now she has backed off again, but is not broody.   
Yesterday I found a shell-less egg she had layed in the straw ( not her normal nesting box ) ... it was properly formed and had a soft membrane around it.   I handled it carefully so's not to break it, and finally opened it with scissors last night - found an ENORMOUS yolk inside it, and the usual white etc.   Threw it out in case of contamination through the fairly thick membrane.  
 
Now - she was doing her thing I thought normally yesterday, when we had a long lot of thunderstorm.    I did see on another site where something unusual ( example was a cat meowing )  can upset the laying process, and said last night  to hubby that she probably shot the non-completed egg out, in absolute fright at the sound of the thunder claps - and they were big.   ( That's my novice thought ). 
 
She has been squatting a lot lately, and squatted again today.   Was in her nesting box this morning, but with no result.   She has eaten ok, ( scratch mix ) and presume she has eaten her layer pellets as per normal.   I won't know the extent of her eating for a couple more days.   
 
MY QUESTION IS :   
 
Can the production of a shell-less egg, lead to or give indication of her being or becoming egg bound ???  I only ask this now, as she was obviously trying to lay something this morning, with no result.   How would I know if she is or is becoming egg-bound.  And is it normal for a chicken to lay 'in fright' a shell-less egg ?    
 
Sorry to put so much questioning to you all ... but I am a bit worried  ... a BIT ??   Quite a lot.   Her behaviour in her run etc. is however normal for her - she is a bit of a neurotic - always on the move and very excitable, especially when she sees our dog who she loves. 
 
Thanking you in anticipation 
 
Cheers ...........AB