I went outside a little bit ago to let our 3 girls out to roam to yard and noticed our 2 easter eggers have bumblefoot..on both feet... Its not bad yet though. The plug is there but there isn't any swelling, guess I caught it early. what the heck causes this??? I've had chickens for 4 years now and have never had to deal with bumblefoot. The only thing I can think off is we added sand to run back in november. Is the sand harder on their feet? This should be exciting now...I get to treat 2 birds with bumblefoot at the same time!