These have lost about 20 workers because they just sit there for hours then die. More dying every day
I will try my best to help because this isn't my cup of tea.
1. Are they foraging less often?
2. Have they stopped eating?
3. If they haven't stopped eating, have you fed them too much carbohydrates? (I have seen ants go diabetic)
4. If they haven't stopped eating and you are sure it's not the sugars, have they stopped eating protein? If not, have you checked your insects for pesticides from the area you caught them/ bought them?
5. Have their brood stopped developing?
6. Has the queen stopped laying?
7. Are you sure you're not under/over 'watering' your ants?
8. Has there been any mold outbreaks? If so, just offer them some rosin and they will clean themselves with it.
Numbers 1, 2, 5, and 6 are sure signs of needing hibernation. The other are unrelated. Well, I guess I can't say I didn't try! You're welcome for any help this may provide