Shama-il Tirmidhi Chapter 025, Hadith Number 004 (146).
Zahdam Al-Jarmi RA.says that we were present in the assembly of abu Musa Ash'ari Radiyallahu 'Anhu. Fowl meat was served for food. A, person from among those present, moved back. Abu Musa Radiyalahu 'Anhu asked him the reason (for doing so). He replied 'I had seen the fowl eat something (dirty) so I swore an oath that I will not eat it'. Abu Musa Radiyallahu 'Anhu said: 'In that case, I had seen Rasulullah Sallallahu 'Alayhi Wasallam eat the meat of a fowl' (come and partake of it without fear. If it was not permissible or disliked, how did Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam eat it).
The object is that something which is permissible in shari'ah must not be prohibited. Break the oath and give kaffaarah. Eating of the fowl is permissible according to all the Imaams. The 'ulama have only stated that it is makruh to eat the Jalalah type of fowl. (Because it eats dirt). The effect of the fowl is hot and moist (according to the physicians). It digests quickly, creates good humour (body fluids) in the body. It strengthens the brain and the main parts of the body, clears the voice, and gives the body a good complexion. It strengthens the senses too.