I have not completed my analysis of the casualty information that I have collected, so I am not able to provide a specific number I can support at this time, but my incomplete answer is as follows:

The official report submitted by Brigadier General Roger A. Pryor, 5th Brigade, Longstreet’s Division for the “engagements around Richmond” were a consolidated report and did not identify casualties by engagement. The report provided names and units listed by killed, wounded, and missing. Pryor reported the following casualties for the 14th Alabama Regiment for the Seven Days Battles :
70 Killed
253 Wounded
11 Missing
Total Killed, Wounded, and Missing: 334

If you analyze the rosters in Hurst’s History of the 14th Alabama you find similar numbers, but with variances. For example, Hurst reports men as killed at these battles who were wounded and died later, because he knew they died.

Analysis of the individual Confederate Service Records at the National Archives also provides similar numbers to what Pryor and Hurst reported, but not exactly the same.

The analysis I have done (which, as I say is incomplete) indicates approximately 223 total casualties on June 27, 1862 at Ellerson’s Mill and Gaines’s Mill (Ellerson’s Mill was not reported separately), and a total of 117 total casualties at Frayser’s Farm (Glendale) on June 30, 1862. This is a preliminary total of 340 casualties for the 14th Alabama for the Seven Days Battles (which as you can see is close to the number in Pryor’s official report.)

As I indicated above, the 223 total casualties on June 27, 1862 was the highest number of casualties for the 14th Alabama during the entire war. (I expect these numbers to change when I do more analysis.)