Re: Question about water for the 2 feral cats
thank you for the picture of the carrier. Have you modified the carrier so its insulated or are you going to cover it once it is cold?
I found this information on solor covers if you havent insulated it yet.
Debbie Peterson of the Chicagoland Stray Cat Coalition uses solar pool covers/blankets to keep her ferals warm during winter. Solar pool covers are used to attract and retain heat from the sun, to keep water in swimming pools warm. Debbie saw them as a way to upgrade her feral cat houses to solar energy! On a 10°F/-12°C night the temperature inside could easily reach 70°F/21°C! Torn but usable solar pool covers can be found curbside on suburban garbage pick-up days. Purchased new, prices vary based on construction and thickness. A 15 mil premium-grade 12' round blanket costs $32. Cut them with standard household scissors. Drape one over your feral cat house silver-side down, and the purring will start. Aim for full exposure to the south. Check the temperature until you know how much heat is generated; it may become too warm inside on milder days! Consider setting up a solar feeding station a distance from the sleeping area.
another idea, depending on your budget, is you could install an outlet to the outside. If you have an inside outlet by the door an electrician can tap off of that to run another outside. I did that for a fountain I installed outside my office window. It cost me $75. Took him an hour to do. That way you could plug in a heated bed or heating pad.