I just got my first two chickens ever - two 2-month-old Delawares. They were friendly as can be the day I got them (three days ago), perched on my shoulder, let me pick them up, and so on. One is bigger than the other but the breeder is sure they're both pullets. The first night when I put them in their coop the little one literally forced herself underneath the big one. I've noticed since then that the big one is acting almost like the "big sister" looking after the little one. They are always right next to each other, and when I come in the run they both follow me around, winding around my legs like cats. Today the big one seemed mad at me for no reason, jumped at my face when I crouched down in their (big) run, and pecked at my leg once. They both refused to go into their coop when I tried to put them to bed; I had to bribe them in with food. Normal? Weird? Any ideas what might be going on?