See if you can do anything to stop the bleeding first. Then, find something quick to disinfect it if necessary and calm the chickens down. Help them breathe somehow by placing them upright and helping them stay that way. You may want to do this as it may help your chickens until more help...
# 1, 2, and 3 should be pullets as they didn't develop as much as the 4th one. 4th may be a rooster but I may be wrong. Normally by 8 weeks if they develop little they should be recognized.
They shouldn't overeat. Animals often have their own way of survival and usually know what they're doing. My chickens figured out what to and what not to eat within a day and never over eat so I believe the pigeon wouldn't either.