I had 14 two week old chicks. About 30 minutes ago, we heard some high pitched peeping and went to investigate. A couple chicks were lying down with their beaks in the bedding. Within minutes, more were looking poor and went into death seizures. In the last 30 minutes, 9 have died, 3 are looking weak, and only 2 are still standing. I am at a complete loss. Temp is good. They have lots of space. Bedding dry. Poop looks good. Plenty of food and water. Both are clean. Nothing has changed in the environment or nutrition. No indicators of anything amiss. Any idea what may have happened? Suggestions to help prevent this in the future? Suggestions to help the sickly ones and save the healthy ones? Thank you in advance.