And another important point I forgot to mention earlier:
Do not add any more birds if you already have problems with the number you have! On the contrary, you might better consider a reduction.
Here are some suggestions:
Stop feeding bread, it causes stinky, slimy poop and diarrhea.
Install a poop board and clean it every day.
Clean the bedding as needed and exchange at least monthly.
Add some apple cidre vinegar to their water. Exchange water at least every other day and scrub the...