These are the non-infectious causes of lameness, normally Shelley hoof or white line abscesses.
The connection between wall and sole is elastic, but is the weak point in the foot.
Shelley hoof, which is a separation of wall and sole, is common but is not usually associated with lameness, although can cause a problem if mud becomes impacted.
In this case, trim the loose horn out in a semi circle to prevent leaving a space for the mud. If pus forms at the white line the sheep will be acutely lame, these abscesses tend to break out at coronary band. If pus hasn’t broken out, very careful trimming may release the pressure. If it has just broken out, leave a week and then trim the loose horn off.
For more information have a look at this fact sheet - sheep lameness, or the AHDB booklet - Reducing Lameness for Better Returns. Alternatively, call the practice and speak to a member of the farm team - 01363 772860.