I think it's certain days, but not sure
They do school field trips Tu-Fri 10:30a-1:30p, as long as it isn't raining and isn't super muddy from a lot of rain. They will allow the public to come during these times as well for a reduced admission price since not ALL of the attractions are open. (The hayride, swings, jumping pillows, bird houses, slides and cornbox are open along with being able to see the animals up close.) You would enter through the Farm Market and pay admission there, get an armband, and have the chance to go explore until 1:30 :)
Thanks! Your answer is awaiting moderation.