Ruling on giving chickens antibiotics that may harm those who eat them
Question

                I have started poultry business and there is an issue of antibiotic resistance in humans. We are trying to reduce the use of antibiotics by using it only when the birds need it. However there is some amount of antibiotic in the commercial feed we purchase from a company to promote better growth of chickens. By using this feed, is my business halal or not?
Praise be to Allah.
	You must limit it to giving the chickens only the antibiotics 
	that they need, because their bodies usually do not get rid of them before 
	they are slaughtered, so humans may be harmed by eating them.

	If there is a useful alternative the we should resort to it, 
	such as using bacteria or herbs, and taking care of the eggs and the place 
	where the eggs hatch, so as to reduce the need for antibiotics, and to avoid 
	feed containing antibiotics. 

	The basic principle regarding that is the words of the 
	Prophet (blessings and peace of Allah be upon him): “There should be neither 
	harm nor reciprocating harm.” Narrated by Ahmad (2865) and Ibn Maajah 
	(2341). Classed as saheeh by al-Albaani in Saheeh Ibn Maajah.

	It is haraam to cause harm to the Muslims in their food or 
	otherwise. Do you not see that the Prophet (blessings and peace of Allah be 
	upon him) cursed the one who contaminates the roads of the Muslims and the 
	places where they sit, so how about the one who contaminates their food and 
	causes them physical harm? Ahmad (2715), Abu Dawood (26) and Ibn Maajah 
	(328) narrated that the Messenger of Allah (blessings and peace of Allah be 
	upon him) said: “Fear the three things which provoke curses: relieving 
	oneself in the routes to water sources, in places of shade and in the middle 
	of the street.”

	Classed as hasan by al-Albaani in Saheeh Abi Dawood.

	Conclusion:

	What you should do is avoid that which will cause harm to 
	people, so do not give medicine to the chickens except when needed, and only 
	as much as is needed.

	Try to give them feed that is not mixed with any impurities, 
	antibiotics or anything else that may harm human health, especially in the 
	period just before they are sold or slaughtered.

	And Allah knows best.