Mini Horses
Herd Master
Tricky 

I've heard of that as well, but haven't tried it. Mustard is supposed to taste terrible I was told.I've never tried it myself - but I've heard of folks blowing an egg & filling it with something staining (mustard dyed blue and such) to find out who's eating eggs.
Thinking about it.Game camera?
BYC has posts that say it works, and posts that say it doesn't.I've heard of that as well, but haven't tried it. Mustard is supposed to taste terrible I was told.
I tried that at one point. But mine are pretty cheap & had enough of a delay between the movement & the recording that all I ever got was multiple hens in a group.Game camera?