What i do is when the pen is vacant i disinfect it 3 straight days and 3 different disinfectant. Anything available in the market as long as 3 different brand sila. Or sometimes 2 different brand and zonrox. Or 1 branded, 1 zonrox and fire/apoy/blow torch.
Apply the first brand all over the pen and then let dry. Don't rinse.
Next day, rinse it and apply the second disinfectant. Don't rinse again, just let it dry.
Then same procedure for the last disinfectant.
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If you are having constant problem in your farm, meaning almost every week some of you animal is sick then you can disinfect weekly the pen but this time you need to rinse immediately because the animal might drink it or lick it. Look for disinfectant that could be use even there is animal in the pen. Just ask your local store for this kind of disinfectant. If ala zonrox will do.