My daughter's japanese bantam hen has a very large crop that doesn't get smaller overnight. I was also checking her for mites under her wing and some mucus came out of her mouth. We have three bantam hens and recently got another japanese. We quarantined the new pullet for a week. She didn't seem sick so we put her in with the others. Now our older japanese hen is acting funny. She moves her head in a strange way and keeps her feathers puffed up. I'm not sure what is worng with her and what to do for it. Any help would be appreciated.