A number of our hens suddenly are suffering from bumblefoot (some bad, some not so bad). We never had this problem before, and the only things that have changed are: 1) we added ducks to our flock about four months ago. The ducks are messy so there's a lot more water/mud around. 2) About two months ago we switched from organic feed to a good non-organic brand (trying to save some money) 3) After we discovered the bumblefoot, we removed all of the perches (which were square wooden rods) and replaced them with new clean round rods. Can switching feed cause bumblefoot? Could it be the mud? Is there something else that I have not thought about? Any insights appreciated.