I am sorry you've had such a time with your birds. I hope you'll reconsider and keep them. You have put alot of time into them and hopefully when you get them through this they'll be okay. Do you have a bird thats handicapped? Remember to give them some probiotics during and after they have these antibiotics to help with good gut bacteria, yogurt is really good for them also butter milk. Keep us informed as too how it's going, and I'll be thinking about you all.
