We just got our first egg yesterday from one of the Rhode Island Reds. This chicken in particular has been extremely friendly and loved to be pet, but now that she's had her first egg she has become hyper aggressive. She's even attempting to chase us (we don't react) and she has bitten a couple of times and drawn blood in the past two days.
Like I said, she used to jump up on a leg when we kneeled down and wanted to be pet, this is really strange for her. She's even acting like she wants to jump up and attack us.
This is our first flock, so this behavior change was definitely unexpected.