Nope, no prescription needed. It's sold in the US as Denagard and imported as Chevimulin-T. Denagard is a liquid concentrate that's kind of expensive unless treating a big flock. Chevimulin-T is intended for pigeons and pet birds and is more affordable if you're just treating a few birds. It comes as a powder sealed in foil packets so the shelf life is probably way beyond the expiration date printed on them.
http://www.bioagrimix.com/haccp/html/tiamulin.htm
http://www.chevita.com/en/products/chevimulin-t.php
One drawback is that it's incompatible with anti-coccidia feeds containing ionophores.
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