Seeking MacKays in Thurso Scotland

Hi. I'm seeking info on grandfather, his brother and my great-grand father. Granddad;s name was Kenneth,he married Agnes Mann of Scotland they were married in New York. My dad Donald MacKay told me that my great-grandfather had a farm outside of Thurso. I don't know his name or his wifes name. We know that he still owned the farm in 1926. Help if you canthanks DMB