I bought 4 nine week old Seabright chicks a few weeks ago. I have about 30 hens in the coop. The chicks have been fine for two weeks and in the last 4 days I have lost 3 of them. They were healthy in the afternoon and dead at night. Could the hens be attacking the chicks and killing them? I live in CT. and have put a low light in the coop to give some warmth to the young birds. Please give me your opinion on what is happening.