I bought 8 approx week old chicks (mixed heritage breeds) from a hatchery nearly a week ago. After a couple of days it was clear that one of the chick was not growing at all and another seemed to be smaller than the others but not so pronounced... but they were feeding and otherwise looked happy. Yesterday I looked in and could see that the others were now double the size of the little one and it wasn't feeding as vigorously as the others... and got pushed around but it was taking food and water. I rang the hatchery and said that particular breed, polish were weaker chicks. This morning I found that chick dead and another (a speckled sussex) - the other smaller one has poop stuck to its bottom. There was no blood in the poop that I could see and the one that died was pooping ok yesterday. This morning I separated the weaker smaller one and moved the others to a fresh cage with fresh bedding food etc. About 5 minutes ago I noticed that another (hamburg) is looking lethargic! I am assuming it could be a bacteria and am boiling their feeding containers and using sterile bedding. We are feeding them chick starter sold to us by the hatchery and they are vaccinated. They have a heatlamp and an area to get away from it if they like - they have clean fresh bedding, food and water - are not kept with any other poultry or livestock (they are on our verandah). what is going on?