Is soil composed of animal manure considered pure, and is it permissible to pray on fertilizers made from pig manure?

Animal droppings and urine are of two types:

1. Droppings and urine of animals whose meat is permissible to eat (such as sheep and cattle): These are pure (tahir), and it is permissible to pray on ground mixed with them, based on the indications from the Sunnah and the statements of scholars, as the Prophet (peace be upon him) prayed in sheepfolds.

2. Droppings and urine of animals whose meat is not permissible to eat (such as donkeys and pigs): These are impure (najis) according to the majority of scholars.

If they remain in their original state without change, the ground mixed with them is impure and it is not permissible to pray on it.

If they transform into another substance (istihalah), such as becoming soil, then they become pure, and it is permissible to pray on ground mixed with them. This is the most correct opinion according to Sheikh Al-Islam Ibn Taymiyyah and others.