at our yard we have about 30-40 horses, geldings and mares are split but everything from newly weened to retired are kept together and we rarely have a problem
my 10mth old colt is kept with his 18yr old mum and my 6yr old companion pony. His mum keeps him in check but he plays with my pony with out any problems, how ever i keep my horses at home so it is just the 3 of them.
She would also be kept at home, however the main problem is she is a filly & all I have here are geldings.
I have 2 geldings that are completely un-interested in mares though so it would be either of them. The 4yo would be the more likely candidate though as then they could be out 24/7 until the end of summer.
She's a fairly quiet girl though & has been used to being in a herd, I've owned her since she was a few days old. I'm just toying with bringing her home earlier than we expected. We always were expecting her to come home but not until she was about 3yo.
We've always kept mixed herds with no problems at all. If you're introducing a new youngster to a herd I would buddy her up with one of the herd members on their own first so they have someone they know before being chucked out with all the rest - helps stop any possible bullying as they have an ally!!
On a side note Flaxen - I would take your colt away from his mum or geld asap or he could get his mum in foal - happened to a neighbor of ours a couple of years ago!!!!
same as above my yearling is out with 2yr old and various mixed sex older horses and no problem in fact much beter disciplined than i could do on my own
I try to let mine live in as natural an environment as possible and so currently have my yearling out with a 2 yr old, 13yr old (to go in foal) and 17 yr old (going in foal)...I find it invaluable for the babies to be around older horses as it teaches them manners and in my situation it works really well. Once those mares are in foal I will separate the yearling and 2 yr old to be together away from the as would rather the pregnant ladies had time to chill without being harrassed by youngsters.
I ran my foal with his mum, and sister and another mare until he was a year old. mare weaned him naturally, but he had the emotional support
then mean me, put him out with my 4yo colt (as I found out he was rather interested in the in season mare.....)
So I put him out with a 4yo stallion, and after the initial sort out, its working out really nicely
Poor little sod had to learn to play boys games though that hes never had to , and the 4yo is so good, but isnt impressed when mounted......