My oldest rooster (2.5) and a 1 year old hen have been showing different respiratory symptoms since winter. The rooster gurgles/rattles when he breathes but acts good. The hen has been shaking her head really fast while making a sneezing sound but also acts good. I thought gapeworms but then found out gapeworms are rare and my chickens would've been dead by now if it were that. Now I've got some hens sneezing every now and then whereas they never used to. The thing is that everyone is acting perfect and it's really slow to develop if it develops at all. I'm taking to rooster to a vet to check him out and see if I can get powdered antibiotics for the whole flock. Do you think it's a respiratory infection? I've never had a respiratory infection be this slow and unnoticeable. If not, then what do you think it is? Thanks in advance.