horse mouth length growth

Question
hello madam, does a horse mouth length grow as the horse grows older. for instance, i have a 2 year old thoroughbred colt recently arrived to my stable. i got a snaffle suitable to his mouth length. as he grows older and older and becomes a 6 year old one, does that snaffle (which i got when he was a baby) become tight? should i need to check his mouth length again and get a new one which quite bigger in length than the previous one and much suitable for him now as a 6 year old. madam, at what age, does a horse growth stop, is it at the age of 4 or 5??

Answer
yes when they become older the mouth becomes wider and you will need a bigger bit check the bit fitting every month to see how it looks when it starts getting tight go to a bigger size by half an inch. the horse is fully grown when it hits around 6 years old. they may grow a little more until they are 8 but mostly full grown and done growing when they are 6