Raising an abandoned chick?

Hi all,
my family and I have twelve hens and a rooster. We have had the chickens since we moved to this house, and we got the rooster recently (four or five months ago). And now, we have a bit of a problem with an abandoned chick!

- about five weeks ago one of the hens went broody, and was sitting on eight eggs. We marked each of these eggs, and three weeks later four eggs hatched, and then hen stopped sitting on the eggs. Unexpectedly, four days later, three more chicks hatched. By the time we found out, two were dead, and one was cold and dying. We dried and warmed up the chick, and then tried to re-introduce it to the hen and the other chicks. This did not work at all!! So it was put underneath another chicken who is broody and sitting on eggs due to hatch in another week and a half, which seemed fine. But an hour later the chick had been kicked out, and was again cold and limp.

We didn't have anything to care for a chick, no incubator or chick feed. So for the first few days it stayed in a bed with the electric blanket on, and ate oats soaked in water. It survived, and it is now a week old (and very very cute, it's starting to grow pin feathers on it's wings!!) We now have it in a snake vivarium under a light - but still don't have chick feed!

So that is my first proper question: should we go and get proper food? Or will seeds, oats, and small bits of fruit and vegetables be ok? Those are basically the things that the chicks being raised by hens are eating.

Secondly, is there a way to reintroduce it to the other chickens? When should we do this?

And finally, one of the chick's feet is "mangled" looking, and doesn't straighten out. It has been like this since it hatched, and we assumed it would fix itself as the chick got older, but it is still like that. Is this a problem?

Sorry for the long post. We are all new to this!