One of my Iceland chicks is acting very lethargic. She was acting just fine the other day and found her this morning not moving and very weak. I gave her some sugar water and she kinda perked up, she is now still weak but is chirping. I already found a dead Iceland yesterday, bot sure what happened I found him dead in the morning. That Iceland was also acting fine the day prior to his death. What could be wrong? Is there anything I can do?