Ducks and geese will do this themselves naturally, before winter and the big migrations.
I really doubt that they hold their mouths open while they shove a tube down their own throat. If they did this naturally then there would be no need for us to do it to them.
Foie has been around for more than 4,000 years, so this isn't exactly a new thing. Tapatalk won't let me copy and paste (wtf?) but on Wikipedia there's even a quote from our buddy Pliny the Elder describing the process.
That's an appeal to tradition...means nothing to me. Pliny most likely had slaves and thought women should be subservient to men but that doesn't make it right. (even if he didn't, I only say that to explain appeal to tradition)
It's already been stated elsewhere but gavage is the least of your ethical worries if you're eating battery-produced chickens for dinner.
We aren't arguing chickens here. I didn't start a post complaining about legislation limiting how many chickens can be kept per square foot or something like that.
This type of food isn't needed, in my opinion. Maybe you can convince me otherwise. But appeals to tradition won't do that.