Hi. I am from South Africa, but check out this website...
Chew Hooves - Pet Supplies - Compare Prices, Reviews and Buy at NexTag - Price - Review.
You can try the butcher. The hooves are really cheap... like 10 for R15, that translates to about $2 for 10. Cheap cheap. And they last a long time.
I hope you find them and I am sure your baby will enjoy them a lot!