K Ryan:
I would be inclined to believe the 1823 Andrew Hichey is the father of the Andrew born in 1873.
The 1821 Andrew had father John while 1823 Andrew had father Peter.
The oldest son of Andrew Hickey and Hanora Brien was Peter born in 1861.
Although you can't trust the Irish naming patterns all the time, in this case I'm confident that the 1823 record is correct.
Roger McDonnell