I have two layers who as far as I know were raised together (recently adopted them both). One of the girls started laying and the other one stood watch over her. Literally. She stood next to her and if anyone came too close she climbed in the nesting box and put herself between the one laying and the offending visitor. She stood by her "sister" every day doing this up until today. Today they BOTH started laying at the same time and wedged themself into one nesting box rather than separating. Is this normal chicken behavior?