Chickens stopped laying

[Flachickman]

I have 2 BSL's and for the past 3 years they were pretty good layers , however about 2 months ago one of them stopped laying and 4 days (and 4 eggs later) they both stopped. I am still feeding them Layena but nothing is happening. They are molting a little and there are some black feathers scattered around the coop. I'm wondering of this is normal. They were 4 years old in November.

 

[Welshies]

They stop to molt. Stop feeding that lay feed and provide cat kibble for extra protein.