How old is she? has she been laying eggs and if so when was the last one laid? could be she is egg bound.
Try letting her sit in a warm tub of water enough to float do this as often as you can and you can also warm some old towels in the dryer and let her lay on them the warm moisture is suppose to help, also do you have any liquid calcium? you can make her a small bowl of water and put this liquid or even tums crushed up into the water and let her drink it. when you have her in the tub gently palpate her tummy down close to the vent and feel for an egg[very gently] When my duck had an egg stuck i actually felt up inside of her for the egg, sometimes if they are very close to the opening you can manually get 1-2 fingers around the egg and gently pull it out. You can also try vaseline in and around the vent. after her warm bathe. If there is a drake keep him separated for now, it would be good if you could do all of this tonight and then put her int a large dog crate or bath tub on warm towels and let her rest checking on her often. After soaking mine most of the day off an on she laid her egg the next morning.
