I have both sheep and deer and have for over thirty years. We used to run deer first in a pen and then would use sheep to eat the rest of the grass. I did that for ten years with no sign of MCF. I then started to run my whitetail with my male sheep and have done that for twenty plus years. Both my sheep and deer have been a closed herd since 2000. I assume my sheep are not carriers of MCF as we have no die off that would look like MCF. I would think you would need nose to nose contact with sheep that had MCF to get your deer sick. Just an opinion.