I come at this from the point of view of someone who wants to breed rats that are good pet animals but also good show animals. Some varieties are easier than others and there are different reasons for it.
Some varieties have health issues, which may or may not make them less suitable for owning and selling as pets. For example – British blues based varieties are prone to having poor immune systems, topaz/buff are more likely to have bleeding/clotting disorders, chinchilla based rats if not carefully bred can produce kittens with megacolon. Most of these can be minimised through careful breeding, but it’s another selection pressure, and the more plates that need kept spinning then the more likely one of them will fall down (or that they’ll all stay up there, but wobbly and ready to collapse with little prior warning).
Most marked varieties are not particularly difficult to breed, but difficult to produce an excellent example for show (I would consider a show rat to be one that wins stars and will be a contender for the supreme challenge in a show, not one that just wins a class rosette and nothing else), and lots of the rats you keep for breeding will not be show suitable. If you’re only intent on breeding a very small number of litters then having a variety that may only give you a quality show rat every couple of years isn’t very encouraging. Some marked are easier than others – Essex tend to produce well marked animals fairly easily, and roans (although they don’t show well for long) often are nicely marked and will win as young rats at least.
Most of the AOV varieties are easy enough to breed good examples of. Things like silver fawn, agouti, cinnamon – agouti based rats tend to have a good long show life, there’s a lot of them about to find crosses of, and so they tend to do well in shows. There is a lot of competition in those classes, so you need a decent one to win, but finding the right starter rats to get to that point isn’t ever going to be difficult either.
Every variety has their own challenges – different shades to get right, nuances of how that particular colour or marking works, what you need to breed to. Realistically, it’s not rocket science, and although some are more difficult than others, the most important part is that you are breeding something you love. It’s much easier to put your heart into it if it’s something you want to do to start with, and much easier to get past the inevitable obstacles if you have more motivation to climb over them.
The pink eye dilute gene (which gives champagne) turns a rat into a much paler version of itself. If you have a black rat, then add PED, you get a diluted black. Black is a cold colour, you add PED, you get a paler but cold colour. Chocolate is a warm colour, and a bit paler than black. If you add PED to chocolate, you get a paler and warmer colour than a version based on black. It’s not that black is making it darker – it’s that the chocolate gene is making it paler.
I’ve seen people advise adding black to a Siamese line to darken up the points, but it doesn’t make any sense and it doesn’t work. Adding black can be useful because you can see that blacks have dark feet, so you can use it to help to eliminate white feet from the line. But it won’t make the points any darker, it will just help you to breed white toes out of it.
The depth of colour of the Siamese shading is dependent on hundreds of other little modifier genes. You want to breed in as many of those as possible to your Siamese line to get good dark points. If you have a black outcross from a dark Siamese line he might carry lots of these modifiers so be useful for darkening the Siamese, but his Siamese brother would be just as useful
I don’t like the idea of a formal mentor-mentee relationship as I have seen it go wrong so many times, and even when it doesn’t end up in a relationship breakdown, it often ends awkwardly. If you are creating a formal mentor relationship, you are creating an expectation – the expectation that the mentor will give to the mentee a certain amount of time and effort and often rats, and quite often their name as almost a “shield” to wear. In return, the mentee will probably be following the advice given to them – the way they feed, their husbandry, their methods and the ethics of their mentor. When the mentee develops their own methods and ideas, do they need to ask for permission to “formally end” the relationship? What if the mentor doesn’t think they’re ready? Minefield!
Probably the one thing I am entirely confident on with rats is that there are as many different and equally correct ways to do things as there are rat breeders. I am always happy to have people over to just come and chat about rat breeding – come and see my setup, talk about how I do things. But I’d also encourage them to go and visit other breeders too and find out how they do things. My way isn’t the best way – but it’s the best way for me and my rats. Your way isn’t the best either, it’s just the best way for you and yours.
The best new rat breeders aren’t the one who had the best/most prestigious mentors – they’re the ones who felt most supported in their journey, who have been given the information and help they need to feel confident in the decisions they’re making (and why). Supporting new breeders is the job of every other breeder they come into contact with in the fancy. I do always feel thrilled and like I’ve done my job as a rat breeder when new breeders thank me or give me some credit towards their success, there is no better ego boost to your heart than to see someone doing something awesome and tell you that you had a hand in it!
It is hugely unusual to see anyone reputable offering kittens for homes that are only a couple of weeks old. Breeders should be interested in selecting which kittens they keep back for future breeding on the basis of best possible temperament, type, and colour/markings.
When you are looking at kittens that are very young, you know what variety they have and what markings, but you cannot properly evaluate temperament or type. So that means you are only selecting on what variety they are – not even the quality of it, since the colour and markings can change rapidly in the next few weeks.
If you do have an interest in breeding to improve temperament/type/colour, you should make decisions on the kittens you are keeping and those you are not as late as possible. This would allow you more time to properly evaluate the kittens, and it’s also better for those purchasing kittens, as you can tell them more about the personality of the rats involved rather than it just being about what they look like.
By properly selecting the rats you keep as potential breeders in the first place, you’ll be able to breed to improve, rather than breed just to create more kittens of a particular variety.