It's not effective mixed in the water, so I wish that would not be posted. To make it more manageable, if you have easily identifiable breeds, you can treat one group of one or two breeds, and then do the next group when you are done with the first, may make it a little more manageable as long as you can easily tell who is who so that no one is missed.
4 foot high is very high for a roost, I try to not have any jumps that are more than 18 inches. Particularly for any of the heavier breeds. There is always somebody who will jump or fly rather than use a ramp. You could also try stacking square hay bales underneath, so they can use them as stairs and it will discourage jumping. Even a hard landing onto the ground could cause a tiny injury that could let the bacteria in.
4 foot high is very high for a roost, I try to not have any jumps that are more than 18 inches. Particularly for any of the heavier breeds. There is always somebody who will jump or fly rather than use a ramp. You could also try stacking square hay bales underneath, so they can use them as stairs and it will discourage jumping. Even a hard landing onto the ground could cause a tiny injury that could let the bacteria in.