Sex Link laying pattern changed

[Auscal]

I have a red sex link (RIR X Delaware) that is abut 2 yr 2 months old. She started laying at 5 months and had reliably been laying 5-6 eggs a week, slowing to 4ish eggs a week over the last winter. She hasn't moulted. About 4-6 weeks ago, she gradually changed her laying pattern, now she is only laying an egg every 4-5 days or so, but it is a huge egg - I weighed the last and it is 91 gms (3oz). Also, the eggs have changed from a medium/dark brown color, to almost white. They also now have "bands" and almost a calcium ridge around the lower third. She seems to struggle laying (no wonder!) and I have almost been concerned at times she may be eggbound. This is from a fairly smallish, light bodied chicken. I'm just wondering "whats happening". Is she basically finished as a layer? Is this just a stage, and she will resume her previous pattern? I am a relative newbie to this stage, and just curious about some opinions.

FWIW, her diet & "lifestyle" is unchanged, and chickens from the same hatching have not had this laying change.

 

[Chick Charm]

It sounds like this chicken is in the decline. It may just be her time. If she has never molted yet in 2 years that may be a contributor. I'm just guessing on the molt thing. Other than natural infrequency......Has she been been checked for worms or mites?

 

[Auscal]

No "visible" worms in her poop - I'm trying to find a vet to do a fecal test - & I guess that's a very unusual request, judging from the replies I am getting LOL.

As for mites - how do I check for them?

 

[Chick Charm]

look under their wings and by the vent. you can see them.

 

[Auscal]

Happy to say, no mites

So, any other comments on her infrequent , but huge egg laying behaviour?