I have a 1 year old barnyard mix hen. Recently she sounds like she’s choking. Not sneezing no discharge. She eats and drinks and lays her eggs. Normal except she sounds like someone’s squeezing her neck. She has a rattle when she breathes. When the day warms up she hides in a shady spot and opens her wings up and breathes rapidly. No other chicken is doing this. She’s been doing it about a week now.