Quote from Stormbringer4729 >>

 You feel that it must be a balmy, 60degrees. 

 (Actually, is this Fahrenheit or Celsius? F would be warmer than the outside, but colder than I'd set my room heating at. C would be nearly sauna temperature. I assumed based on your US location that it's F)

Azzure is intrigued and follows Gyrig down the rope ladder, curious about the balmy temperature.  

Balmy, 60degrees Fahrenheit. Balmy compared to the outside that is.

When Gryrig reaches the bottom of the ladder, he pauses and has a good look around. Perception 9

The giant bats are not hard to spot. The floors are slick with bat guano. If you travel thru its pitchblack here the squares are 5ft wide the ceiling is 30ft up

give me a nature check

Btw those without dark vision cant see the bats

 Nature:16

Quote from Touschka_ >>

[...] From his backpack, he extracts a hooded lamp and lights it to provide some light (being plain human, he has no darkvision)

 (Hooded lantern provides 30ft normal light, and and additional 30ft dim light. I think that should be enough to see the bats on the ceiling)

Duncan:

As he reaches the end of the rope, Duncan sees the bats dimly lit by the hooded lantern.  He draws his shield and moon-touched Longsword, causing it to shed cool moonlight around him so he can see, but he attempts to walk quietly so as not to disturb the bats. 

“Perhaps we can move by stealthily and not disturb them,” he whispers hopefully.

Stealth:  13

Azzure easily sees the giant bats with his Eyes of Night.  A sudden exhalation of breath from him alerts anyone close that he has seen something.  

Nature : 14 

He prepares to take flight to avoid sounds and make himself quieter.  

Stealth 17

Torman nods in agreement about trying to be stealthy.  As they move forward he does his best not to slip on all the guano.

Stealth  19

Azzure tries to keep his dwarven plate mail quiet as he moves through…

Stealth : 12 

Kat tries not to be bitter about her wasted spell that would have made sneaking past giant bats trivial.

Stealth: 22

Quote from Spiderwrangler >>

Kat tries not to be bitter about her wasted spell that would have made sneaking past giant bats trivial.

Stealth: 19

 As everyone starts to move sneakily, Gryrig suddenly realises that he has a similar spell to Kat's. He casts Silence on a point on the ceiling to cover the bats in the spell's effect. Between the magic effect and the groups efforts to remain silent, Gryrig is optimistic that they should be able to go by undetected. 

(I should have thought of that earlier).

Those with a nature check above DC15 Believe that if they disturb the Giant bats they might be attacked. Ether way, the bats would start flying around and make allot of noise, if light is shown on them.

The Silence spell mutes the problem of them hearing, the group but......

"Keep it dark! No lights until we're through, pass it on.", Kat whispers to the folks nearest her.

Gryrig hastly lowers the hood of his hooded lantern, dramatically reducing its light and leaving the Bats in the pitch black once more

(so, 5ft dim light only now)

Duncan:

The soft glow from his sword only reaches 15 feet (and 30 feet dimly), but Duncan nonetheless mostly sheathes it so it only illuminates the ground at his feet.