One of the processing places in Maine that I have been to is Tabor Homestead in Berwick, that's probably the one you're aware of because it's not that far into Maine. Last year they had a note on their website that said they only do white meat birds. I don't know why, but that's what it said, so they likely wouldn't do the spent layers. As far as I know, they only do chickens and turkeys, so there wouldn't be a problem with lambs before Easter.
The other place I have been, and the one I now prefer, is Ken's in Biddeford.
If you are just selling to a few friends, I suspect you can get around all laws. It's likely that it is legal for you to sell live birds to your friends, then transport the birds to and from the processors for your friends. In effect, if your friends order before the slaughter you'd be OK. Of course, this depends upon your friends being cooperative. And, even if they are happy to cooperate, it's not a bad thing to understand the laws. It would never have occurred to me that there was anything wrong with transporting processed birds over a state line, though now that you mention it I would not be surprised if there was special consideration if the birds were intended for sale.
Tim
The other place I have been, and the one I now prefer, is Ken's in Biddeford.
If you are just selling to a few friends, I suspect you can get around all laws. It's likely that it is legal for you to sell live birds to your friends, then transport the birds to and from the processors for your friends. In effect, if your friends order before the slaughter you'd be OK. Of course, this depends upon your friends being cooperative. And, even if they are happy to cooperate, it's not a bad thing to understand the laws. It would never have occurred to me that there was anything wrong with transporting processed birds over a state line, though now that you mention it I would not be surprised if there was special consideration if the birds were intended for sale.
Tim