I have 17 chicks that range from 3 weeks to 8 weeks old. I put them in my raised pen today in hopes of leaving them outside. It's completely enclosed with a roof and perfectly safe, but the 3 week old is a bantam I got from work due to him being a little sluggish when we received them. The rest are at least 5 weeks old. It's forecasted to get down to 66° tonight and it's been raining all afternoon and is going to continue all night. I placed a waterproof cover over the top and sides and left the bottom open for ventilation, but I'm worried it may be too cold for them outside tonight, any thoughts?