I have only dipped pigeons once in all the years I've kept them. Mid way through the old bird season in 1979, several members in my club had problems with depluming mite. Unfortunately, I had 4 birds with the problem too. Thinking that this would spread to every bird within my loft, I contacted a pigeon health help line, who advice to dip every pigeon with a product called "Pigeon Dip ". Old grandfather and I duly carried out the instructions. About a week later the birds were out in the rain and they were completely soaked through, as the dip had taken all the oil out the feathers, and they struggled to fly when wet. It took about a month for the feathering to come back to a decent quality to repel the rain. The product used for dipping the birds certainly sorted out the problem, as no other birds suffered from depluming mite. I would agree with you Walter that you need to give the birds several weeks to enable the feathering to come back to a good standard.