I have 2 baby silky chicks, they were hatched in a incubator on the same day and are now 1 week old. One is yellow and one is grey. When they first hatched the yellow seemed a lot stronger and was soon running & jumping around where as the grey one took a few days to find its balance properly. Now, the grey one is regularly eating & drinking from the feeder, running about and has even started scratching today. The last couple of days the grey one seems to have grown lots and is now double the size of the yellow one. The little yellow one doesn't seem to be eating or drinking, no natural pecking instinct. It will drink when dipping its beak in water on a spoon but then won't follow the spoon down and naturally peck! Its poo is still very watery - when it does occaissonally poo (its just a small green drip) When cleaning the box out is seems to get cold very quickly and spends most of the day sleeping while the other one is jumping around. It makes a small pipping noise a lot of the time and looks a bit weak today. As the grey one has grown it seems to be pecking the yellow one a lot today. Just visited the local chicken auction and a man has told us that the yellow one must have a disease and it must be killed before the grey one catches the disease. The chicks have been kept indoors, we've cleaned their box out every day, giving them fresh water & food, we don't have any other animals in the house. Made sure we've cleaned our hands before & after handling them. Does this sound possible that it has a disease and should we take it out?? Really don't want to kill it, but then don't want the grey one to catch any disease any loose both of them. We're new to being chicken owners, thought I'd done plenty of homework but with them acting so differently I'm stumped. Grateful of any advice.