My 7 month old Easter Egger, Jami Hendrix, is acting strange. BTW - these are my 1st chickens. She is sitting on her roost all fluffed up and will not go outside. The other 3 go in and out all day. She is not spending the time in the nesting box all day and is splitting the rest of the time perched on her roost. She is eating and drinking and looks great but her behavior is concerning. The outside temps have been in the teens and now in the 40s but they have the coop heated at night (around 45). Should I be concerned?