Needing Info on All-in-One powder

[QiyeTLyriQue]

I just bought this because a couple of my hens have the sniffles, occasional sneeze. Since I've never used this before I called Jedd's (where I bought it) and asked if there was any egg withdrawal period; the lady didnt know.

Before I return this, I was wondering if anyone has personally used this and knows what the egg withdrawal period is? I don't eat my chickens but I do eat their eggs, so that's where the concern is.

Also, if I can't use this, does anyone have any recommendations for something I can give my chickens to clear this respiratory issue before it gets worse?

Thanks In Advance!