If their area depends on air conditioning and you are away from home and are in area where power outages are common, have a neighbor check if the electric goes out. Some a/c units need to be reset after a power failure. Check your electric while at home and make sure it is adequate to run air conditioning. If you have central air and want to check, the easiest way is to plug an answering machine into the plug that the air conditioning system is on. When you call home it will pick up if it is working, if the electric is out and the air is not working it will not pick up...do no use the battery back up here.
Winter.. Ferrets enjoy cool weather but not weather under 40 degrees for any extended periods. Since they don't like heat, do not locate them near the heating units in your home. Put a lot of old sweatshirts and T-Shirts in their cage if they get cold they can burrow and cuddle in these for warmth.
It's a good idea to keep track of your ferrets weight. A small digital scale is good, these can be purchased as postal scales at your local office supply.
I can not stress enough, until you get to know these little guys you have to be aware every second they are out and playing. You have to know where they are, or they will get into trouble. Escape to the great outdoors is not uncommon. They can move items several times their size and weight and very easily pry open a door or window that has been left ajar. If it is there, a ferret will investigate it.
Ferrets love to stash things and will make an area they feel is safe to put all the little things they find laying around that they think should be theirs. Under couches behind drapes, they are most inventive. They will even go into furniture through the dust covers at the bottom, into dressers from underneath if the bottom is exposed, behind radiators, into box springs of beds, that gauzy stuff there is easy stuff for a fur face.
They will also decide to eat the strangest stuff, they love rubbery items, foam and velcro. If you wear sneakers watch out for the inner soles, that is good ferret stuff!! Those little toys you get in kids meals are a good attention getter to a ferret, and could spell disaster if eaten.
I am not a veterinarian nor do I have any medical training. I am a very enthusiastic ferret owner and am telling you things based on my experience, and those of other ferret owners. My first and best advice to you is if you are in doubt of anything call the VETERINARIAN.
I will give you an overview of medical problems that can occur and the symptoms that I know of. If your ferret is experiencing any of these, or even something that is not listed call the VETERINARIAN. If you feel it is of concern, it probably is. Don't wait to see if anything goes away, unless your VETERINARIAN tells you to wait.
This is especially true if you are new to ferrets. That phone consultation, or visit may cost you a lot less, if you do not hesitate, and the life of your ferret may depend on it. If your little guy is obviously hurt, stepped on, sat on, squished by something, or is bleeding from any area IMMEDIATE VETERINARIAN attention is required.
Get to know your ferret as well as you do yourself. His behavior, sleeping habits, eating habits, pooing and peeing. Get use to checking that litter pan and food dish this will be your first sign that something is wrong. Ferrets have short digestive tracts. Generally what they eat comes out the other side within 3-4 hours. If they have eaten something which is not part of the normal ferret diet it will come out the way it went in. As long as it comes out, everything should be fine.
Ferrets need hair ball medication and when you give them this, sometimes you will notice the hair coming out, kind of clumpy. This is good, you don't want it blocking their intestines, it could develop into a hair ball and then you will have a problem.
Once again I say the best advice you can get is through asking questions of your veterinarian.