Automatic door problem

[rje ma]

I have an automatic door that operate on a sensor. It has worked flawlessly for about 2 weeks with my chickens getting into the coop in the evening before it closes for the night. Last night at dusk I looked at the coop and noted my chickens were in for the night at dusk as usual. About 15 minutes later my wife looked and said the chicks were outside and the door was closed. I was puzzled why they came back out and got stuck outside. Well I went outside in the dark and shined a light on the sensor to open the door. I figured they would just go in. Wrong! They refused to go in . I even picked up a couple and put them through the opening. Not only did they come back out but the one bird that was inside came out too!. So I went inside and checked the whole coop to make sure it was ok. I did not see any problems. Nothing inside, not to warm.i finally had to carry them in one at a time.
I have a protected run completely inclosed. I have not seen any predators so far so I was tempted to just leave them outside. However they were all hurtled together and clucking like they were scared so I put them inside. Any thoughts anyone???

 

[Den in Penn]

One thing that may have got them back out. Was it lighter outside then inside the coop?

 

[rje ma]

It was slightly lighter outside than inside but not different than any other night.

 

[Den in Penn]

I will say this and it may not have anything to do with why they came out. When it gets hot they extend the time they forage much closer to dark then normal. They spend the day trying to stay cool in the shade as long as they can. When it starts to cool in the evening, they then go to forage. So heat can change their behavior.

 

[rje ma]

Thanks, that could have been the case that day.the last couple of nights they have gone in on time. Thanks again for the good input hope I can return the favor sometime