What age to start jumping a horse?

[brigit]

This is quite a controversial topic but just wondering what age you have/would start a horse jumping? Interested to see as there are many different views on this.
For example my aunt will break in a 3 or 4 year old in a week and have it jumping a small course by the end of the week ( one extreme) then I know a girl who waits until 5 or even 6 to start jumping as she says by then the bones and muscles are fully developed.

 

[MileAMinute]

I will start jumping my guy properly in the summer (he'll be 4.5yo).

So far he's gone over coloured poles and trotting poles, occasionally raised. He has the odd jump or 2 on the lunge if there are some up.
Might pop an odd crosspole but nothing serious. Aim is to do 1ft6/2ft SJ end of summer/autumn, then he'll have a break again over winter.

 

[Nightmare before Christmas]

Ill pop a fence or two at 3. Jumping at shows by 4. Totally depends on what the horse is aiming for!

 

[Jools2345]

not before 5yrs,

 

[Goldenstar]

At the end of backing and riding away I will lose school twice perhaps just to see.
At four I would start with pole work then onto small grids and single fences then baby clinics I might or might not do a few little shows in the autumn but not a lot.

 

[HBM1]

Just started loose jumping my 3yr10m old..but he is very well developed. I have a 3yr old I wouldn't dream of jumping as he is huge but underdeveloped and immature