One of our Buff Orp chicks has always, from day one, been a lot smaller than the others, and slower to feather out. For its first few weeks of life, it was also more sluggish, and stayed under the heat lamp a whole lot more. For a while, we kept expecting it to be dead every morning, but then there it would be, alive another day. Ever since I moved them outside a couple of weeks ago, the "puny" chick has been acting full of vim and vigor, perfectly normal. Still smaller than all the others, but sassy as all get-out. Today, we sat out in their yard for an hour, feeding them cooked brown rice, plain yogurt, lettuce and a few grapes. Puny was the first one to grab a treat, and led the others on many a chase around the yard with her "treasures." In other words, all was well a couple of hours ago! Just now, when we went to put them to bed, my husband opened the "people door" to the coop, and there lay Puny, right under the (now turned off) heat-lamp, doornail-dead! Not a mark on her, no sign of distress, no evidence of picking, NOTHING. Just dead. Any thoughts? Do I need to be worried about the rest of the birds? They were hatched on April 4th, so are just over 7 weeks old.