Small Finches

Question
My partner and I started with two Zebra Finches in a small cage indoors, we have now built a large outside building with large outside flight and have now got loads of Zebras, some Heck finches, Bengalis, Java sparrows, diamond doves, and a number of Chinese Painted Quail. When first introduced to new surroundings we mainly had the Zebras and Bengalis, a friend purchased the others for us at a show in the north of England. All seemed well until they were introduced together, they were fine for ages then all of a sudden a few Zebras seemed to take off and fly upside down and land on the floor, these birds still get around ok but can't fly. Others will fluff their feathers up and look listless, (I think this will be Red Mite as iv'e seen then on the walls). Can you give any indication to the paralysis of the Zebras? Can you also suggest a Mite spray that can be sprayed readily whilst food and water are still on show.
Many Thanks and kind regards,
Bill.

Answer
I've never heard of such a thing before. I suggest taking a couple to the vet and getting a treatment you can do at home on the rest of them.

Also, I suggest you move the cage indoors. I have never liked the idea of pet birds living outside. Many types of pet birds have been domesticated so long that they no longer have the immune system to deal with the diseases that are outside.