Hi Dizzydog
There seem to be some hogs who scorn eating the food that’s offered and prefer what they find for themselves. I have one who visits at the moment. It forages on the lawn and unfortunately under where the bird feeder is during the day – although I don’t think much is spilt from that, it has a very large tray. But I put a bowl of kitten biscuits down right where it normally forages and it went very close but completely ignored it. A few feet away there is more food which other hogs enjoy, but not that one. So maybe the hogs you have there are similarly self sufficient.
But if the bowls were previously very clean, are you sure cats weren’t eating it because they tend to lick the bowls clean whereas hogs will often leave a little bit.
