I have bought some babbie chicks from a hatchery this year on Febuary 15th and raised them inside untill April 15th. After the 15th I started to put them outside in a chicken tractor during the day and brought them in a night, soon after I began to leave them outside with a heat lamp. They have all done great up untill the time I began to leave them outside full time with a heat lamp at night to be on the safe side, because it was warm enough, then they started to die off at about 60-70 days old everyday some times 2 a day. It was very upsetting, I tried and tried (I thought about everything i could) to help them but nothing worked . I started off with 84 chicks, and after every day of loosing at least one, occaisonally every other day. Untill I had about 20 left around the end of May then they stopped diying, which was really, really great!!. All up until this very day. Now they are starting to die again at about 1 every other day. This is very, very, very upsetting. What did I do wrong and can anybody help me? Is this gona start effecting my other chickens that I did not get from the hatchery?