I have one to three sick french black copper maran chicks, four weeks old. Very lethargic and feathers look all puffed up. I just isolated them tonight, they arrived from a breeder 1 1/2 weeks ago and looked fine until two days ago or so. Not much info. to go on I know, but I should know more in a day or two as they are out of the big flock now so I can really keep an eye on them. Any advice at this point??