Well, I’d be inclined to over order slightly anyway…sometimes chicks die and they aren’t noisy when young. Will the agency count your chickens and fine you for one extra? Maybe…but maybe not. Obviously, a lot extra is a problem, but I’d not be very worried about 1 extra (unless it’s a male, who becomes obvious with crowing). Plus, if they are behind a fence or not easy to find/see/count then it also should be ok for you…unless you have restrictions on roosters.
I’m not suggesting you break the laws, I’m just saying that I would not be too worried unless you have evidence that they are very strict or a neighbor that might cause issue. We’ve bought, hatched and raised hundreds of chicks…it is common to have at least one just up and die the first week, and sometimes we get one that dies by 4-6 weeks old. Chickens are prey animals and do not show illness unless they are very ill, and sometimes they just are hatched with a defect you can’t see.
When we sell, we just take them to a livestock auction and drop them off, and we get a check in the mail. A friend sells on CL, but I don’t want that hassle, so I use the livestock auction.