Hot weather?? Problem solved I think!

they will drop in number then pick up. drop in number pick up  it will be like that though out the year . i have the same thing from my girls an yes its very very worrying  .

i got 13 out of 16 girls today i was pleased with that but am dying to hit the full house

Mystery solved - I think - though solution is a bit of a poser!

When mowing the big section next to the chicken paddock I kept finding egg shells .. Then Saturday I found just the white of an egg -no yolk and no shell - in a nest box and a walk round outside the run discovered several more egg shells broken.  Just one egg on those days and those when I opened up at just before 7.

Undaunted - and bravely without the benefit of morning coffee -  I kept watch and a large crow has cheekily learned to go into the chicken coop and steal the eggs!!!
He is always sitting around when I go up with the mash porridge at about 11 but I thought he was after that and would shoo him off the run.

This morning saw me coffee in hand and sitting the run while the girlies had breakfast and went in and out the coop with the result of 7 eggs and a very disgruntled crow who even came down when I was sitting there!

So mystery of the wildly fluctuating egg numbers is solved I think but I really can't always sit there for 2 hours while they decide to lay!  I can't see how to keep the crow out and let the chickens in as the smaller run is over 100 ft long by 20+ foot and I cant afford to enclose that lot.  The thought that springs to mind is a shotgun as it can't be common crow behaviour- anyone else had this problem??

You could see if you know anyone that has a larsons trap. For crows you will need a side entering.  Unfortunately it has learnt that eggs are good and where to get them so there is only one other definite answer. Catch and kill.
There is a temporary answer that may put him off.  It can work with magpies but not necessary with crow. (magpies are more nervous) . Try hanging a stock carrot bag over the entrance of the coop.

if you are going to make one try this.
http://www.ew.govt.nz/Environmental-information/Plant-and-animal-pests/Animal-pests/Magpies/Construction-of-a-magpie-trap/#Heading1

I have been told that magpies like top entry and crow side entry. So you will have to change the plans slightly.

I've also been having trouble with crows going through the pophole. Don't have trouble with the magpies as next door has his trap operative at the moment.

Does the carrot bag work, Rough?

I was intending to try a fly screen, one of those plastic strip ones. I have bought one but not cut it down to size yet. 

Good luck with getting rid of your crow, however you decide to do it. We have a rook who hangs around after the girls and I'm sure he would try to take eggs: but fortunately when he made his way into the run (which is fully enclosed) he was severely upset by not being able to fly out, plus Jean got at him when he was on the ground and pecked him almost to death  . Don't think he'll be trying that again