Horses changing color when relogging into the world

Relogging into a world into a world to find that the type of horses i had found had changed into stallions from chestnuts

I had just created a world and found 5 horses and 2 baby horses all brown on the edge of a desert and plains biome. I set my render distance to 4 chunks because my computer lags a lot when Minecraft crashed. I relogged into the world and searched for the horses only to find that they were now stallions (white horses).