Personally, I don't like Halloween. The holiday started as a pagan celebration. Then, the churches decided to supplant it as the night before All Saints Day. Halloween began as Hallowed Eve (a holy evening). Some adults would dress as saints and go door to door singing hymns and reciting poems or scriptures. Children would ask for "soul cakes." Now the holiday has devolved into a celebration of witches, ghosts (demons), and destructive pranks. It is the result of Satan's evil influence over mankind. Ephesians 6:12 (NKJV), "For we do not wrestle against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places."
However, most people think of Halloween as a time of fun costumes when children dress up and gather candy. If you can participate in this event without considering the rest of connotations, then you could distribute candy with a clear conscience. However, if it bothers your conscience and you cannot give candy to children to God's glory, then absolutely do not do it. 1 Corinthians 10:31 (NKJV), "Therefore, whether you eat or drink, or whatever you do, do all to the glory of God."