Answered by Sidi Mostafa Azzam
I recently prayed at Masjid al-Haram and I noticed that there were bird droppings on the grounds of this blessed majid as it is open-air and birds fly all around. What is the ruling about praying in a place where bird droppings are clearly present? I have heard that there is another opinion in the Shafi’i madhab that holds the feces and urine of lawful (to eat) animals to be pure, similar to the position of the Malikis and Hanbalis. Is there such a valid opinion in the Shafi’i madhbab?
Feces as Filth
As indicated in The Immaculate Raiment (2.3(2-3)), feces are filth. They are filth even if they are from edible animals. I am not familiar with any relevant difference of opinion in the Shafi`i school regarding their filthiness. Imam Nawawis Minhaj al-Talibin gives no indication of any difference of opinion.
Removal of Filth
As mentioned The Immaculate Raiment (2.2), whatever your body touches must be free of unexcused filth. If during your prayer you touch an unexcused amount of bird droppings, your prayer is invalid.
There is a general principle that whatever filth is normally a hardship to avoid is excused.
Excused Bird Droppings
The imams have mentioned that amongst the examples of excused filth are bird droppings, provided that there is no moisture, that the droppings are all over the place you wish to pray, and that you do not deliberately stand on them. Thus, bird droppings may be excused, even though they are considered filth.
And Allah knows best.