Your fence needs to be replaced with something safe that a foal cannot get through, especially if you plan to wean the colt on the property or if you plan to keep him entire and next to your stallion. In that case, you would need a different type of fence.
You asked a question. The type of fence you will need depends upon your answers to the questions I asked you. I don’t care what you do with your colt, I was trying to answer your question accurately. There is no need to be rude.
Good luck.