Bantam hen swollen chest

[DixieDame67]

my lil banty hen has a huge swollen chest or breast, i picked her up and its like a large mass gell like, any ideas what it could be?, I was putting the chickens up right at dark so i didn't get a photo should i bring her in and seperate her from the others, she is eating and drinking fine,

 

[TreeFever]

This could be her crop!
It is where a hen grinds up food before it goes to her tummy.
In the evening it will be all full from eating all day.