I had 3 chicks hatch on day 17 of being under a broody hen. Two of them seemed fine but one seemed very lethargic and it was panting pretty bad. I thought maybe it was too hot outside so I brought all three of them inside. I had them under a heat lamp and they did fine for a few hours. I checked on them just now and the one that was panting is dead and the other two are very close to death. I think that maybe the heat lamp was too hot? Honestly I don't know. What do I do to help them?