I got three new pullets (one gold laced and two silver laced Wyandottes) just over 2 weeks ago. They are in a smaller coop separate from my other girls as I planned to keep them quarantined for a month just in case. I noticed the gold one sneezing occasionally within a day or two but all three were peppy and eating and drinking as they should so I didn't pay it too much mind. One of the silver ones didn't grow like the others though - she stayed really tiny and over the last two days went from very peppy to lethargic. I gave her vitamins but didn't separate them and found her dead in the coop this morning. I feel awful for not bringing her in but I honestly didn't think it was that bad. I had a feeling something was weird with her the whole time as she was tiny but don't have much experience with younger birds so wasn't sure. Now, the gold one is still sneezing. The other one looks fine but I am worried that they will meet the same fate. I have given the coop a thorough cleaning and am giving them Nutri drench and extra protein. They don't seem too perky though. Does anyone have any ideas what this could be? We are in Ontario, Canada and it's gotten chilly the last couple nights but the coop is dry and draft free so I don't think that's it. Any tips on how to best look after them would be much appreciated. I really don't want the same nasty surprise when I open the coop tomorrow. Thanks in advance!