My project for today is to build a creep feeder. I've raised so many batches of ducklings this year and I want to be able to let the range around the yard during the day after the first couple weeks. The older ducks have gotten used to seeing younger ducks and leave them alone, but the problem I have is that the big ducks eat all the duckling food. I want to take a little portable poultry tractor, and convert it into a creep feeder by cutting a door in one side that is large enough for ducklings up to eight weeks to go through, but too small for full-grown ducks. I'm not sure how big that would be, and I want to get it right the first time so I can convert the leftover bit of wood into a hinged door, so the tractor can be closed and still used for its original purpose sometimes (for instance, letting younger ducklings in the yard but still contained). So I opened up my trusty Holderread to the section on creep feeders, and this is what he says: "A space 4 inches square is satisfactory when breeds weighing 7 to 9 pounds are kept. For smaller breeds, such as Mallards, the passageway needs to be approximately 3 inches square to keep the old birds from entering." So, two questions: Are Runners 7 to 9 pounds? Or are they "Mallard"-sized? And, perhaps more importantly, does "A space 4 inches square" mean the dimensions are 2" by 2", or 4" by 4"? And is 3 inches square 3" by 3" or is he talking about the total area of the opening? Help! Thanks!