I have a small flock of 8 chickens that includes a brown Leghorn. She's about 7 months old and is a daily layer. I have two others, a Leghorn and a Brahma, that are the same age ad also regular layers. The other five consisting of 2 sex links, a Wyandotte, an Easter Egger, and an Australorp have not started laying yet. However, the brown Leghorn sounds like she needs to blow her nose. She also occasionally shakes her head and I can hear the same sound. There are no other symptoms. She is eating well, energetic, and a regular layer. Any speculation from anyone what could be the problem?