That's really up to you - you'll get some who will say a goat owner should never allow their goats to have horns and list 800 reasons why horns are bad, then you'll get some who say they've never had an issue ever and have both horned and hornless goats.
I, at one time, had both horned goats and hornless goats. Never had a problem - and the horned goats were pygmys and nigerians and the hornless were bigger breeds. However, I have since rehomed all my horned goats because I just like disbudded/polled goats more. JMO
It is something you need to be very careful with. It honestly depends on the individual goat that posesses the horns. If he/she is already an aggressive or dominant goat, it might not be a good idea.
We had a girl that was second in command in the herd who had her horns still and everything was fine until one day it wasn't. We went out one summer afternoon and our girl had cornered one of the younger ones in the barn and gored it. It was a sad day for our little upstart herd. "Big Mama" the horned goat found a new home in a herd with others of her kind and we decided that horned goats are not for us.
if you have several goats together with horns and have only one or two in with out horns they will be low man on the totem pole. The other goats might pick on them more. I have one doe with no horns in with 18 other does with horns and she doesn't have the easiest time of it dispite the fact that she is by far the biggest goat in the barn. I love the doe, but wish I had thought of that before I purchased her.
If your goats have a lot of space in which to roam, there is more chance of horned goats getting their heads stuck and experiencing problems, too. A friend of mine on a large, sprawling farm once had a horned goat get her head stuck in a fence . . . and a wild dog pack found her before the LGDs could reach that part of the pasture. Not good.
Just something to think about while you're "collating data." Hope that info helps.
altho one good reason for being "horn-free" is if you have children. goats tend to toss their heads around and it wouldnt be worth it to endanger little ones.
i know folks who say that 'God put the horns there for a reason'..and we are leaning toward "it will be easier to sell disbudded babies.'
we had a horn-less goat get stuck in a fence so not sure there is a better answer than 'do what you think is best.'
All my five goats are horned and the only problem I have had, is you need to take extra care, when they toss their heads about, you need to make sure they are not in the way.
One caught me this evening, it's happend our few times now, but nothing serious.
I don't know about mixing horned and hornless, not something I have done, but I don't think I would, after watching my lot beat the living @@@@ out of each other, I don't think I would put a hornless goat in with them.