As you can see from the variety of advice, there are many opinions on the best time to wean. You CAN successfully wean as early as 2.5 months, as far as the foals' nutritional plane and physical development, if you know what you are doing, but for social development I agree with the post-ers that advise to leave the foal with mom for 5-6 months or even a bit longer, if the mare's condition is OK.
That said, your younger foal will probably be fine at 4 months weaning with his 6 month old buddy, as long as the younger foal is not significantly smaller and/or getting bullied away from the feed by the bigger, older foal. Your idea about taking away the older foal's dam and leaving him with the other mare and foal for awhile is not a bad idea actually, as long as the other mare is not agressive toward him, and he has the opportunity to get plenty of feed-- a sturdy "creep feeder", designed so that the foals can get to it but not the mare, might be helpful.
I also wanted to clear up the statement, >>> horses loose the ability to digest milk around 3-4 months.
That is not exactly true. Horses can digest milk even as adults. In some countries, they even feed milk to mares who are raising foals. Mare's milk DOES start to gradually decline in quality after around 2.5-3 months, but it s a GRADUAL decline, and is still beneficial to her foal for months after it has passed its nutritional peak. For the older foal, the benefit in staying with mom is mostly social-- the foal learns horse behaviors and gains security and confidence from his dam. |