Chickens are small creatures, so just about 3-5 minutes a day of massage is good. You can stroke them and talk to them, the rest of the time, about 5-10 minutes. Or, until they let you know they are done. Some chickens are more receptive than others.
For the music, I have found that a tablet and bluetooth speaker works fantastically. My husband was given a free tablet with his new phone, but he had no use for it. Well, I took that tablet and put some music on it for the chickens. I ordered a bluetooth speaker, that can receive the signal up to 50 feet from the tablet, and it can play music up to 10 hours on a single charge, but actually lasts 12 hours.
I paid $20 for a bluetooth speaker on Amazon. It can be used outdoors too.
I had to try different types of music, before I learned they only like soft, melodic sounds. So, they have an extensive music library: Spanish guitar ballads, Irish Folk, American classic country, some elevator, Floyd Cramer piano classics, Beegie Adair, Joni Mitchell, etc. My husband just laughs...I call it their chicken radio station! Ha-ha!
But they are happy and joyful chickens. The music also confuses the bob cat that has been stalking them. He never is sure if I am out there. When friends or family stop over, they too, prefer to sit outside to listen to the music, and watch the chickens.
But, a radio can work good too...I used one for my parakeet.
It's all good!
God Bless
