I currently have a mixed herd of 5 and will be adding one more horse.
This is a new herd as my old gelding (28) just lost his friend (older mare) and he could not be alone. The mare's place was taken by a 14 year old mare who immediately took over the top spot and now is the boss of the field (he used to be).
We have since added 2 more geldings and 1 mare. The second mare is pretty low in the pecking order but she is also the most recent addition and I understand that if there is another mare in the field the other mare will remain top above the new mare (it is her nature to be below another mare).
I am reluctant to add a 3rd mare but am in the market for another horse. If I do get another mare that would make 3 mares and 3 geldings turned out together. Currently there are no problems with the geldings, I just have an uneasy feeling about adding another mare instead of a gelding and I don't know why.
I am open to advice and anecdotes of other people's experience.