I have two young male employees,who are poor. They do not fast during ramzan. If I feed them during day time,will it be gunah on my part.since I have lots of left over food which I don't want to throw

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Fasting the month of Ramadan is one of the great pillars of Islam, and a Muslim is not allowed to neglect it. The person who breaks the fast during Ramadan without a legitimate excuse will be committing a grave major sin, as stated by Ibn Taymiyyah.

If these two young men breake their fast without a legitimate excuse, then they should be admonished and reminded about the seriousness of this matter.

Shaykh Ibn Baaz,  was asked by a woman who cooks for her husband to eat during the day in Ramadan and break his fast without a legitimate excuse; am I sinful? He said: “Indeed, you incur a sin by doing so and must repent from doing it, because by cooking for him you are helping him in his disobedience to Allah, while Allah Says (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression.} [Quran 5:2]

Allah knows best.