SICK HEN,NOT LAYING

[nannie]

1year old pullet,white leghorn.has not layed in week.butt area looks swollen.i felt her butt tonight.It feels sort of soft and like its full of fluid.What could be wrong? I gave her and a few more chickens tylan 50.2 shots each.she layed through that.when she did lay,it was a nice size egg large to say.IS there anything I can do for her?

 

[seminolewind]

Chickens do not lay every single day, well most take a little vacation now and then. What does her poo look like? What does the abdomen feel like? (between the legs and a bit forward ). Does she look uncomfortable like an egg is stuck?