Good link Kathy and I'm bookmarking. However, I believe it's for soluables, not injectables.
For swine the withdrawal for powder is 48 hours, but 14 days for the injectable, from that I would feel safe saying for chikens it's 72 hours for the powder and no less than 14 days for the injectable. But I am not a vet, nor do I have any medical training, so everyone should do a little research of their own.

-Kathy