My ball doesn't want to eat

Do balls stop eating in the colder months ?
I live in Texas, and I didn't have a problem feeding my ball python this past summer. He used to take 1 small or medium size rat every 7 days with no problems. He haven't feed in about almost three weeks, looks like he is not interested in food. I have been keeping the same temps all over the year, doesn't look sick, so I wonder what's going on.
It is ok his behavior, do I have to wait or should I take him to the vet ?
Thanks for your help !

Well, I know females sometimes go off feed during breeding season, I'm not sure if males do the same thing, but that could be a reason why. I wouldn't start worrying about it until he's been off feed for a long time(months). As long as he's healthy, you'll be fine. Sorry I couldn't be of more help. Good luck!

Mine had also been fasting up until this week. He went about a month and a half before his appetite came back. It seems this is a common occurrence with ball pythons. Mine also exhibited the lack of appetite right around this time last year.

My males eat year round, but that's not to say someone else's will. BPs are funny like that.

Males will also fast during the breeding season. My male's been doing the exact same thing. I have been feeding him rats, but he's been off feed for about a month and a half now (I started pairing in October). He's getting pretty lean now, not skinny, just lean. I think I'm going to throw a mouse in there instead of a rat to see if it will make any kind of difference.

BPs can go off feed this time of the year once they reach sexual maturity. Like stated above, some wont. I wouldn't worry unless I see signs of illness or obvious weight loss.