Taking the suggestion of Huntin-Pony I am posting this question here…He is (Dante) starting to bite me my 17 year old son, the other 3 month old colt, his mother the rope essentially everything. He also reared up on my son yesterday. Dante has a halter and will walk with a lead rope. Any suggestions…
He sounds like a typical bratty 3 month old colt, especially if his dam isn’t laying down the law.
I would start with the shock-and-awe treatment for misbehaviour like biting and rearing, as in, scare him without hurting him. NONONO!!! And chase him off. Make a dramatic show of it. If that doesn’t elicit a good startle enough to make him reconsider the behaviour, I’d give him a smart pop with my hand or a whip somewhere other than around his face. Usually a few well timed “KNOCK IT THE **** OFF!!!” and a stinging smack get the point across much better than nagging, which usually just turns the misbehaviour into a game. Escalate as needed for his temperament.
Be careful when reprimanding when he is on the lead, because you don’t want to flip him over.
Good luck.
From my experience with colts.
If he is getting any grain or supplements do your best to keep him from getting any, though you do need sure he gets salt. Once he gets the message that You. Will. Not. Put. Up. With. That. gradually allow him to steal some grain from the mare. It is HOT now, his growth should not suffer too much (I am assuming he is still nursing.)
If he is getting no grain and isn’t stealing the mare’s grain you might cut back the mare’s grain some (heresy), her milk may be too rich for his level of emotional development.
As for the grain for about 3 weeks now he has been eating right along with the mare and both the colts (10 days apart) have been eating very well both grass and grain as a lot of times throughout the day mommas lightly brush them back when they try to nurse.
It’s normal colt stuff. If teeth touch a person’s body the person turns into a big, nasty roaring lion! Person turns back into pleasent being when teeth do NOT touch the person. (Pertains to rearing also.) As for bitting the other colt and his mother—let the horses work that out for themselves. It is how he behaves toward people that he needs to understand.
Mine will usually try that once or perhaps twice and that’s the end of it. Im sorry but I will put the fear of God into them if they try and bite me, rear, strike or try and kick me. Mr Dressage Whip will sting their chest, their front legs, their hind end pretty definitively, quickly and hard if they try. That usually puts an end to it and if they do try again, its a half hearted attempt only.
A friend who is new to the breeding end of things and handling babies contacted me last year and said she was no longer able to lead her yearling filly through the arena from turnout as she would rear and strike and spin and try and kick her so she had to go the long way around, through deep snowbanks, etc and did I have any suggestions. Yeah - put the fear of God into her too and nail her hard - make it quick, make it count and then ask her if she was capable of being a respectable young filly and that would be the end of it and if she threw another fit she got spanked again until she realized that it was completely unacceptable behavior and would now be dealt with each and every time it happened
I find if they are being jerks they are made to work, Small lunge circles at a walk on the lead both ways. Stopping, backing up, forward. Stopping again and turning right and left, lungeing both ways again (just in the walk) so that they 100% have to focus on me and what I am asking them to do. Then we try going inside like civilized youngsters and the whole way in I will make them stop and start. Turn and walk away. Come back again. make a fuss over them when they get it right and make them work longer if they don’t
I also never set them up to fail from the get go. I never have a baby as the last horse in so they are panicked by the time their turn comes. They are first or somewhere in the middle. I will also change it up a bit so they have to be alone in the barn for 2-3 minutes until the next horse comes in and they have to learn to deal with it. I think if you make them listen to you and focus on you where they don’t always know the routine 100% of the time, they don’t get as upset when you deviate from their routine a little bit and they are able to cope with things a bit better
Good luck! 
Mine started the “here’s my teeth” game early! Like, the first two weeks… He learned quick that I am not a chew toy by a well placed and well timed reprimand that scared the snot out if him. I was ready for him to grab at me, and since his mom is officially a marshmallow, I used my hand to swat him a good one on the neck as soon as his nose came at me. He spun and ran so fast I thought he was gonna fall over! Omg! 
I have not been on the menu since…his dam, my husband, and my stepdaughter however…
im all all for dealing with the issue in the moment and moving on immediately after. It seems to work for me
I am an awful disciplinarian physically (can yell pretty good but that grows old) so what works for me is to channel my inner alpha mare - as recommended by so many COTHers. Watch a herd, find the alpha mare, and study her reaction when anyone or anything steps out of line. It is swift, clear, sharp and leaves no questions. And when it’s over, it’s over. She doesn’t apologize but just goes on like everything is back to normal.
This worked wonders with our yearling and is still needed once in a blue moon. She is very smart and sensitive so I have been lucky that I rarely have to “alpha” her but when I do, as others stated, I make it count. She considered kicking me once at a month old and it has never ever even crossed her mind to consider it again with me or anyone else. I also think consistency amongst handlers is important or the smart ones look for the “weakest” link, so to speak - it is really all about human safety now and in the years to come.
Occasionally I need to wear the alpha mare hat with my seven year old mare who thinks she rules the farm - never enjoy it but helps me as I realize that what I am doing is no where near as tough as a “real” alpha mare would be!
Now my husband is less than enthralled with wifely alpha mare behavior, so I do try to leave it at the barn…
In my experience, the BEST way to teach a colt manners is another horse. My colt was a brat around 2-3 months last year…until I put an uncle gelding out with him and his dam. Mom tolerated the leaping, lunging, nipping, and coltishness. Uncle Gelding did not allow any horseplay or foolishness. No rearing, no striking, no biting, and don’t even DARE disrespect his space. Rotten colt grew up fast with 18 hours a day of turnout with Uncle Gelding and mom. Aside from his zero tolerance policy, Uncle Gelding was a quiet, safe, and gentle buddy; his reprimands were not dangerous, just well-timed and always consistent.
Rotten Colt turned into Gentleman Colt within two days. I had tried to curb the nipping, nibbling, and pushiness when leading; I was very firm with him but he viewed everybody as a potential playmate to boss around like his dam. After Uncle Gelding’s companionship, my colt was all manners: polite to lead, dared not touch you with his nose (much less teeth), and stood like a statue for the farrier. Some life lessons are best learned from elders.
[QUOTE=Jackie Cochran;7635741]
If he is getting any grain or supplements do your best to keep him from getting any, though you do need sure he gets salt. Once he gets the message that You. Will. Not. Put. Up. With. That. gradually allow him to steal some grain from the mare. It is HOT now, his growth should not suffer too much (I am assuming he is still nursing.)[/QUOTE]
I would not reduce a foal’s intake as a first choice…of course, depends on how much and what he is getting.
But this is just normal colt behavior from a foal that has probably not been disciplined from the very start. Probably more loving & kissing than discipline. And you are just starting to see the results.
You need to do some halter work, where you can control his movement; get him going backwards, forwards, sideways…and he ALWAYS needs to be looking at you and paying attention.
And if he is aggressive, you need to be aggressive back. DON’T make it into a game (because that is how colts play…ROUGH!), but be serious. Use a dressage whip or whiffle bat or broom or whatever and smack the living bejeezus o/o him! Chase him o/o your space.
NOT on head or legs, but anywhere else it’s not likely you will hurt him.
Boys are boisterous…you need to start discipline almost from Day One.
To give you a different viewpoint, this can be a sign of physical vigor, sometimes sweet stud colts do not bounce back as well from illness or accidents.
Ah, the joys of making a boy horse into a responsible citizen. Sort of like raising a son.
