Feely, 39, most recently played worked out for the Bears, but he only appeared in four games for them last year following an injury to Robbie Gould.
He converted three of his four field goal attempts and was five out of six in extra points to go along with three touchbacks.
Henry, 27, is a former fourth-round pick of the Eagles back in 2011. He lasted three years in Philadelphia before he was waived at the start of the 2014 season. However, the Lions later gave him a shot, but he was once again cut loose a few weeks later.
In 2014, Henery was just one for five in field goal attempts and didn’t miss an extra point attempt.
Hartley, 28, had spent five seasons with the Saints before he was released in December of last year. The Browns signed him to a contract at the end of the 2014 season, but elected to release him shortly after the draft.
Last year, Hartley appeared in two games and converted all three of his field goal attempts and his two extra point tries.