Help: is my chicken sick? Pics attached

[dobee13]

Hi all

Speck seems to be acting normal -- her bossy and inquisitive self, eating just about anything I toss her way. However, I noticed this morning something going on on her underside. I picked her up and even felt it and it didn't seem to bother her at all. It feels fluidy -- like a balloon. I hope it's not something serious -- we lost a chicken last week and my daughter is so sad, it was her pick (and one of my personal faves!) Any info is appreciated.

Pics below are from her behind

 

[FeatheredFreind]

How old is she? Is she laying her eggs okay?

 

[dobee13]

She's a year old and her eggs are fab...a little on the small side, but she lays every day without fail.

 

[chicken-herder]

I don't know but this link might help it has pics too for comparison! http://www.tillysnest.com/2012/12/reasons-for-missing-feathers-in.html
All the best to your girl!