Thomas Boyd was born in 1547. He was the second son, but first surviving son, of Robert Boyd, the 5th Lord Boyd, 5th Lord Kilmarnock and Margaret Campbell. As eldest son of Robert Boyd, the 5th Lord Boyd, he assumed the lordship upon his father's death in death in 1590.
1568 (13 May) - Fought alongside his father at the battle of Langside for Mary, Queen of Scots.
1590 - Inherited the title Lord Boyd on the death of 5th Lord Boyd
1592 (12 Jan) - Resigned his whole estate to the King. He obtained a new charter thereof, "erecting the same into a free Lordship and Barony, to be called the Lordship and Barony of Kilmarnock" to himself for life, with remainder to his son and heir apparent, Robert, Master of Boyd, in tail male, remainder to "heirs male," thereby excluding the heirs general. Under this grant Thomas, not improbably, became Lord Boyd of Kilmarnock. He died June 1611.
Thomas Boyd married three times.
Firstly, before 1568, Margaret, 2nd daughter of Sir Matthew Campbell, of Loudoun, by Isabel, daughter of Sir John Drummond, of Innerpeffry (p 165).
Secondly, he married Jane Stockdale, youngest daughter of William Stockdale of Green Hamerton and his wife Dorothy Mill.
He married, lastly, Elizabeth Wallace, who survived him. 
Thomas and Margaret had eight children as follows:
Marion - married James Hamilton, Earl of Abercorn. 
Isabel - Isabel, according to Robertson, married John Blair, but Collins' Peerage states that James Stuart of Bute, (d. 1662) married Isabel, daughter of Sir Douglas Campbell of Auchinbrick and Isabel his wife, daughter of Thomas, Lord Boyd, which must mean that Isabel married twice. 
Agnes - She married Sir George Elphinstone of Blytheswood. 
Thomas had one natural (illegitimate) child, Andrew.
Cokayne, George Edward, ed. (1912). Complete peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, extant, extinct or dormant (Bass to Canning) Volume 2. London: The St. Catherine Press, ltd.. pp. 261,262.
It may be possible to confirm family relationships with Thomas by comparing test results with other
carriers of his Y-chromosome or his mother's mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
This Thomas seem to mismatched with this mother and siblings. The 2 brothers (with a mother of Jean Kerr cited) do not have a brother Thomas according other sources I have found. Given a date of death is cited as 1611. I suspect this is the same same as Boyd-2074. Upon merging remove the mother of Jean. His birth day would then be much earlier also. Or do you have other sources?