Bumblefoot caused by bare wood...

[chickensioux]

We used to have a wooden ramp for the chickens to come out of the coop on. I was dealing with bumblefoot with 2-3 of my chickens. The vet said it was caused by the bare wood ramp or roosts giving the chickens splinters. We switched our ramp to cinder blocks piled like steps and made their roosts out of natural branches. I have not had bumblefoot since.
Maybe a coincidence but it worked for me.

 

[chickenman33]

could be but i would still be on the lookout

 

[speckledhen]

They can get bumblefoot from ANY abrasion on the foot. I sand and lightly oil my roost periodically, but if they scrape the foot on a rock or walk on the woodpile, it can do exactly the same thing. I'd think concrete blocks, as rough as they are would do it, too. Remember, you can fix everything about your coop but you cannot sanitize and smooth out acreage like many have. Take this from someone who had dealt with bumblefoot on and off for years.