I found my silkie breathing through her mouth. When she breathes she sounds rattlie and gurgly. She also makes a sound every time she breathes. I felt her throat, It rattles when she breathes. it feels like she's congested pretty badly. She will shake her head every now and then like she's trying to clear it out. I also have another hen that's gurgling when she breathes. I was thinking it could be allergies? or pollen? I have no clue. Their water is clean and I haven't fed them anything unusual. Help please!