hard abdomen

[Lisak3]

My 3 year old Barred rock named Betsy has a hard abdomen. We noticed a poopy butt yesterday and some lethargy. We kept her inside overnight, gave her a warm soak and fed her yogurt and crushed boiled egg. Any ideas before we bring her to the vet? She doesn't appear to be waddling or tail flapping.
Thank you for your help!!

 

[Meg-in-MT]

Does she act like she's trying to lay an egg and do you know when she last produced one? Is she eating and drinking?