One dead and one with a hole in its head!!

[Sue Gremlin]

This looks to me like the work of another chicken.

 

[Eggcessive]

Make sure that your chicks are not overcrowded since they they seem to be injuring each other. If some are older or larger, they may need to be moved into the larger side. Vent pecking leads to cannibalism. The back of the neck scalping is a common place for injury from a bully. The injured chick should be separated until the wound is healing well. Are they eating a chick starter grower as mist of their diet?