Nesting, then egg song.. but no egg!

Hi all,

I have a 18 month old RIR hen who has always been a good layer. The past maybe six weeks she has not laid. The other hens slowed down also, but we put this down to the extraordinarily wet weather we have had here (the city even flooded this week - luckily we are on high ground). The sun has finally come out and the RIR has started going back to the nest as if to lay, but sitting there for about 30 mins before coming out of the coop singing her normal 'egg song' and taking a drink and then going about her normal business - but no egg!

This has gone on several times. She is eating well, drinking well and pooping normally. Her diet and general behaviour have not changed. They all free-range during the day in our large backyard, eating the very green grass while having free access to the coop with pellets, shell grit and fresh water. Their diet is also supplemented with fresh veggie scraps.

Any ideas??

 

She did the same again today... and she's not moulting. Not sure about laying internally either. She was funny when she first started laying - she nested and sang the egg song and walked out of the coop. I ran over and there was no egg! Walking back to the house she stopped, and her first egg just 'fell out' while she looked utterley confused.

Fingers crossed it's not a serious problem....