Sick Female Muscovy Duck

Three weeks ago, one of our layers, one year old, began her molt and looked pretty bad per usual but then she stopped eating and even moving around was a chore for her. Our ducks are free range and while they are not afraid of us, they don't like being handled either. Two weeks went by before we finally caught her. She does not have any visible insects, ticks, fleas, or mites on her feathers, under her wings or around her vent. Her eyes and nose are clear. She has a wheeze when she breathes. We fed her extra protein (coqui frogs) and papaya. Hey, it's Hawaii. Both of these foods are treats that they dearly love. She seems over it now and is eating like a horse. Her feathers are coming back in. She lost half her body weight and now walks very stiffly. I think I will be lucky to ever get an egg out of here again.

I am freaking out because another duck is exhibiting the same symptoms and she is NOT molting. Slight wheeze, drinks a lot of water, little or no movement and walks with a slight limp (imagined?), and will let us pick her up which is probably the most disturbing symptom.

The only over the counter antibiotic I have access to here is Oxytetracycline.

Any ideas? I have a duckling coop I can isolate her in.

It may be bacterial infection, in which antibiotics may help. But it also sounds like it could be aspergillosis, a fungal infection and that requires different medicine.

Well, the original sick one is really irritating the other ducks. She barrels in and eats until she can't swallow and when she gets the food down she charges in again. I hope we are over that insanity. The damage to her legs looks permanent. Her gait is very stilted. Oh well, we thought it was all due to her molt. Thankfully she survived our ignorance.

The new sick one responded amazingly well to the antibiotics. She's not completely better but she is walking around again. She was isolated and spent most of the day in a 20 gallon tub of water. We will finish out the course of antibiotics. She drank an incredible amount of water today. Is that a response to the antibiotics? She voided a thin foamy nearly clear stool towards the end of the day and ate with the rest of the flock.

The antibiotics may have played havoc with her intestinal flora - I would give her probiotics. Yes, I think the thirst could be related to the antibiotics. Hard to be sure without diagnostic tests (I am thinking kidney strain). Could well be just that her tummy is upset. I would try offering her her favorite treats.