Persian Blackheads are NOT even Persian, they are South African. They are a breed of the "fat-tailed sheep" category, a category which is known for having fat tails, hardiness, drought tolerance and usually able to browse and graze as opposed to pure grazing of many pure European breeds.
The fat of "Persie" sheep is exceptionally soft even by comparison to other fat-tailed breeds, and is extremely flavourful, with very low melting point.
When cooking a sausage like this, you really want to keep the temperature under 100⁰ Celsius. Why?
Because the higher the heat, the faster you cause the moisture inside the sausage to expand as water reaches boiling point. This causes rapid expansion as the water turns to vapour, which puts pressure on the casing, causing it to burst. Keep it low and slow.....