Does this work for younger birds, too? That's a good option to know, but I just received my order of chicks today (YAY!), and one looks like pasty butt. I cleaned it up with warm water and paper towel. It hasn't been acting strangely, still eating, drinking and socializing, and occasionally picks at its butt on occasion since the cleaning.The flush is 1 tsp of Epsom salt dissolved in 1 cup of water. You administer one full syringe of the liquid to each chicken in need. The number one reason this is used is to treat vent gleet...aka "poopy butt". A single treatment followed by ensuring that the chicken has plenty of access to fresh water is typically sufficient to treat the condition. (I also follow up with the addition of extra vitamins and probiotics to their feed and water.) The ES flushes out their system.
I've also used this treatment on chickens that seemed to suddenly be "unwell" but for which I had no sure diagnosis. It's pretty amazing stuff and has always resulted in a rapid overall improvement of the bird, even during times of high stress, such as during heavy molt. That's actually when I see the most vent gleet too, is during heavy molt...especially if the hen continues to lay eggs regularly during the molt.