My dd had her first fun horse show yesterday and suprised me and i think herself by doing amazingly, she got 1st for best turned out and 3rd in her ridden (beat kids who were ten years older then her) and then got placed in her jumping class ,They all just went over trotting poles I am biased as a mum when I say I think she is really good for her age, but the owner of the stables was chatting to me after it finished (she was one of the judges) and said how well my dd was doing and she showed a lot of potential. She mentioned she would like her to come up more often (she already has two lessons a week) and offered us the pony that she rides on loan (they dont normally loan them out) she said that looking after a pony and doing all the care would bring her on so much more. So for £10 a week my dd would get the pony for three days and he is hers. While I know she would jump at the chance I am not sure it she is a bit young. With the care side she would struggle to muck out as she can just about pick up a shavings fork, I have no problem helping her we had a blast on Sunday turning her pony from a mud monster who had just come in from the field into a sparkly gorgeous boy. It is wonderful to be around horses and ponies again  She enjoys it so much and I know if I asked her she would bite my hand off  I just wondered if it was a bit much a bit young ?
With younger children it's inevitably the parents who take on the brunt of the horse care anyway. Either because some jobs are too physically demanding, or too dangerous, or it's too cold, or the children just lack experience to make the right judgement call, etc.
The question is more, are you interested in a share for your DD? Sounds like you are, so go for it!
It's worth getting a written agreement so that things are clear with your YM and clarifying what will happen in the cold weather in case your DD finds 3 days a week to be too much.
I agree with Booboostoo. I think at 5 it's more a question of whether you are prepared to take on a share, because essentially it would be you who is responsible for the pony on your share days and who ends up doing the bulk of the work. If you are happy with that, and the pony and terms of the share are suitable then go for it!
Dd14 has had ponies since she was 4. IMO You will be doing 90% of the work. It's a huge commitment. There will be days when she wants to do something else. She will succumb to all of the usual childhood illnesses and need time off. Winter will come and she won't want to go out in the cold. You won't want to go out in the cold. She will hit walls in her development which will upset her and will take time and effort and encouragement to work through. It will cost you far more than £10 per week! If you are happy to have a pony for you to look after, and to sometimes be a little hard and push her to live up to her responsibilities, then go for it. I not, then stick to what you are doing.
Oh, and get her and you, some rubber gloves and a bucket. Shavings forks are the work of the devil and should all be put in a rocket and blasted into space! Pick up the muck and put it in the bucket. Seriously, its FAR FAR FAR easier. Especially for a small person!
I agree, it really depends on whether YOU want to be looking after a pony. If you're happy to do everything related to caring for the pony with DD just pottering around trying to help you, then go for it.
DS (almost 5) has a loan pony, we love it! He has great fun brushing him, tack cleaning, and helping to poo pick at the weekends. But I do do most of the work, and we've had to get into a bit of a routine so that its enjoyable - e.g. All jobs are done before riding, as afterwards he's too tired / hungry / getting a bit bored and wanting to go home.
It was hard work over the winter, when we couldn't ride much but there was even more to do (usually I ended up doing all the work, and on riding days - probably only once a week - DH would then bring DS down for a quick ride, then take him straight back into the warmth afterwards while I sorted out). But I think that the discipline of horse care has been a good lesson for him (and i like that he knows what is involved, and doesn't just think that horses look after themselves). Buy her some child sized tools/ wheelbarrow etc, that has helped DS to feel like he's making a contribution.
I agree that the care will be down to you. I wouldn't be leaving a 5 year old in sole charge for any length of time - i.e. not longer than it would take you to nip to the loo, or have something quick to eat. At that age, you'll be the one doing all the mucking out, catching, turning out, tacking up, rugging up at a minimum. You'd also have to be the one to alert the owner to any health concerns you have on your days.
She's not too young to get benifit out of this, and I am sure she will learn a lot, and as the owner will be around, it's not like you are taking sole responsibility for the pony's well being.
Cost wise though, I would find out what your £10 a week covers. For example- who is responsible for keeping the pony shod, who is responsible for paying for any feed used on those days? Check there are no hidden costs. Discuss exactly what is and isn't allowed, and get everything in writing. If you are going to take the pony off the property at all (e.g. hacking) then you will need public liability insurance, but this can be got relatively cheeply throught the BHS.
It could be lots of fun for you and DD, but only if you go in with your eyes open.
To be honest i think they just see how much she loves it and are letting her have him for a very small price. We don't need to shoe him or anything like that and they have supervised access after school for her to go up and spend time with him. She also gets to ride him for 30 minutes each day she has him.
When you say they have supervised access for her to go up and spend time with the pony, tell me you will be there too? We have a super-safe little pony for my kids who is as good as gold, but I would not let my kids (2 and 5) hang out with him, groom him, feed him, etc without responsible 1 to 1 attention from a knowledgable person. A pony only needs to shift his weight from one foot to another to inadvertently stand on a child's foot or even knock them over. A 20kg child in a daydream vs 250kg pony-on-a-diet trying to reach that elusive blade of grass is an unfair challenge!
Other than that I don't think 5 is too young, but as others have said there will have to be a lot of input from you. My kids are very keen, but have days when they are tired, don't want to, etc. Even the 9 year old who comes to help me has off days occasionally. But your DD will definitely come on faster if she is riding regularly. Even if she gains nothing more than an increase in confidence around and on ponies this will stand her in good stead in the future.
As has been mentioned, make sure you have public liability insurance. Even little ponies are big animals, do not underestimate the pickle they can get you into! (My best friend currently has a public liability issue she has been able to pass on to her insurers. The BHS is a good place to start looking. Also the Pony Club, if you sign your daughter up.)
I won't be leaving her on her own for a while yet, she is brilliant at the riding side for her age but obvioiusly does not know how dangerous even a 10hh pony can be, he stood on my foot the other day and i winced so it would be even worse for her. There are 4 people there to supervise them but she can be quite shy to start with so i am looking forward to helping her out.
When she rides on her loan days she gets a lesson a week with her instructor and the for the other two days i can walk next to her while she rides. I have already helped out in her lessons and walk with her so have an idea of what i am doing
Sounds a great deal (almost too good to be true) and one I'd be jumping at in your situation.
However as Saggy, and others say, it will be down to you to look after it as per the terms of your agreement.
DD has been mega keen and competing regularly since she was 3 and currently has 3 ponies. She does her share of stable chores on a daily basis. However she is 10 and we still wouldn't let her go down to "do" them by herself. They are precious animals who need adult supervision.
Sorry i didn't mean on her own i meant with the 4 girls who supervise them, they have already said because she is so small that there will always be somebody with her if i am not there. But to be honest i am happy to stay and help - it's lovely to be around horses again and to see the enjoyment she gets out it as well, i have never seen a child so happy to pooh pick Poor Rene gets to hear all about her day at school and what she is having for tea etc. He will have to learn to zone out !