VAT is on total turnover, not just VATable supplies.
There is no need to wait to reach £77k to register but in most cases it helps. In the case of your business unless you can put your prices up you will have to take the 20% hit yourself so if your profit is less than 20% of your turnover it could end up with success killing you.
Just to make this clear, my answer assumes that you are neither a charity nor an education or cultural establishment.
Entry Tickets Pony Ride Tickets
Both standard rated. A service is being supplied and the purchase of the ticket is merely payment for that service
Gift Shop - depends what you are selling. Generally you will find most items are standard rated (also see the snacks reply below)
Animal feed so people can feed the animals
Interesting one. For you to purchase it would be zero rated but to sell it to the general public as part of an entertainment I would say that it becomes standard rated on the sale
see this notice as it's not a cut and dried answer and wouldn't mind hearing others input on this:
Hope that helps get you started but really yoiu need to have a dig around the links from those links posted above to give you a clearer picture.
Good luck with the business and if you need any further information and pointers just post on here and someone will generally be around to help,
kind regards,
Shaun.
__________________
Shaun
Responses are not meant as a substitute for professional advice. Answers are intended as outline only the advice of a qualified professional with access to all relevant information should be sought before acting on any response given.