I am hoping that someone can help me out with a few questions and maybe someone else may have experienced these same weird occurences...

First off I have had my breeding colony of ASF for about a year now. I originally purchased rats from 5 different colonies and started off with about 50 breeders.
I did this to avoid any serious inbreeding issues.

I have bred them with success for this entire time without any weird happenings until recently when I noticed that my weanlings started scratching alot. Soon after they all started loosing there hair and go almost completely bald before developing the adult coat. After the hair grows back they do just fine and I have fed all these off because I did not want to introduce anything genetic to the breeding colonies.

Now with that said I am extremely OCD in insuring they are not deeply inbred.

I breed just about every color pattern their is and it seems to have gone across all the colonies and has since stopped. I check them for fleas, ticks, mites the whole 9-yards and can not find a single thing that would lead me to believe they are under attack by any of these blood suckers.

I feed all my rodents quality lab block and a vita rat mix made up of fruits nuts seeds and grains. I only give them the vita rat feed every other day and only a sprinkle as a treat so that the lab block is the staple food source. Fresh water is available daily and changed regardless of the resevoir level every 2 days.

The only thing I can think of is that I recently started a few new colonies and wanted to put all the color patterns of the like together and try to figure out the genetics a little more... Again not inbreeding. In doing this I had to replace a few females that were in with nursing females to accomplish this. So here come the questions...

1) Could the change of females and the nursing had anything to do with it? The original female that dropped the litter remains with her young but the possibility of new females and them nursing is my question. Could the other females milk affect the young? I didnt think so because of the community raising throughout the females.

2) Possible food allergy? I have used the same lab block since day one and never had these problems before. Possibility of contaminated food source? i.e. food purchased was spoiled. Not likely to me because I always buy it when they have fresh shipments. Lab block of choice comes from the SUNSEEDS company located here in florida and is spot on to mimic the more exspensive brands yet it is still not cheap in reality.

3) Possibility of food allergies do to vita rat mix? it contains a mixture of all seeds and grains along with nuts and dried fruits.

4) Possibly weaning to soon? I always insure they are no longer on the mothers teats before moving to raise up bins but I figure not to leave anything out.

Other than that I am at a loss. Hopefully someone else has had this happen and can pass some insite as to why. Thanks for all of your time in reading this long rant and thanks 2 all those who can help.... J