I gave for free some friends of mine some chicks I hatched of my own flock that was extra. They have never had chickens before. They & their kids were very happy with the babies. They have had them three months. They came to me today and stated all of them, every juvenile is dead. They all died. They wanted to know why. They stated they had them in their 100% enclosed coop/pen and the gate was locked with no signs of vermits. The birds just appeared to have dropped dead where they stood. Some of the birds were inside the house while some were outside. No missing feathers, no bits, no nothing. I asked if their child might have got confused and feed something they was not suppose to eat and they adamantly said no. I asked if they had any signs of sickness, no again. It was not cold last night, around 68 degrees. I asked if their feed might have been moldy. They said they would look but kept it in a dry place and it had looked fine. I don't know what to do. My chickens had went through molt and have only laid a few eggs since then because of winter coming on. I feel real bad. I don't want to give them more in a way since they don't know why they died. I don't want any hard feelings but they were free to start with and I have no way to replace them at this time. Plus, they kept asking me what to do with them. What do you think? Should I replace them? Has anyone had their whole flock just drop dead? It was about 20 birds. All my flock is great with no signs of sickness. I do have my tested once a year and some of them was tested again about 3 months ago when my daughter showed a few.