I have a BR pullet/hen who is 15 weeks. Today I found her hanging out by herself in the house while the others were enjoying the fresh water and scratch. I don't see any outward symptoms or wounds. But she definitely wants to go in the shade and sit down. It's been very hot here until the last couple of days. My suspicion is a laying instinct is starting up or perhaps she might be trying to lay the very first egg? They're still a little young for that aren't they?