Help chicken stopped laying

[Chick2chicken]

HI,
one of my chickens stopped laying she was the first to lay from my flock and she had been laying practically an egg a day until now. Yesterday she didn't want to leave the coop she stayed on the roost with her feathers all puffed up. She didn't even want to eat the food we offered. Finnaly we put her in the run and she drank a lot of water and didn't pay much attention to the feed, which is 16 percent layer feed. When we came out to feed the scraps to the chickens she lurked behind not very interested, this worried me because she usually loves scraps!
I don't know if she is egg-bound she is not waddling and she is straining a bit and she had some constipation.
Is there any other reason she would stop laying?
What should I do?
Thanks
-Chick2chicken

 

[sassysarah]

Could be broody, hens do not lay when they go broody. does she sit on the nest a lot?

 

[sassysarah]

If not that, she may be getting picked on by the other hens at night and does not get sleep.