Haven't been for about 4years now as ds getting a bit past that, but it always used to be a really great day out. It's lovely for the dcs to get close to see all the animals properly, and at certain times they can feed the lambs/calves whatever, and hold the rabbits and guinea-pigs. There were also toy tractors and diggers they could ride on whilst you sat and watched, and a brilliant outdoor play area with a big trampoline and swings and stuff.
We go a couple of times a month (season ticket very good value). No bad bits - well, if there's coaches in it can be bedlam in the playbarn on a wet day. But all good. Kids love the tractor ride. Enjoy!