# Keeping male litter mice



## Teenybits

I wish to optimise my mice living space as I have limited space. I read that it's impossible for male mice to be in the same bin. Is this really true? I am keeping the males a little older before culling for my cats. The male mice are together all the time and now about 5weeks old


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## meromar

I believe (?) the general trend for an average petshop-variety mouse is to at some point expect aggression of some degree between bucks housed together. But I do know for sure that its highly line dependant, so it may or may not cause aggression depending on the source of your mice.

If it were me -- and I am no expert whatsoever -- I would continue housing my bucks together as usual (its great that youve kept them together from a young age!) and just keep an eye out for any serious problems. Mild aggression on occasion as a hierarchy is established and maintained may be par of the course, but just keep your eyes peeled for more serious instances. 

Of course, this is just what I personally would do... I can't endorse it as The Right Thing ©, as no one knows your mice better than yourself. Best wishes with your bucks friend


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## Teenybits

Hi meromar, they are going to be my first male babies growing up. I am new to them and I gotten them from another breeder whom I guess won't be able to tell me much. I did keep them together as I read that the chances of litter mates getting along are higher. Yes, I am keeping an eye and this is my first trial bucks after already having reducing some bucks babies down; it was not easy but right to do so.


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## Torin

How long bucks can stay together does seem to be a behavioural trait that is very line dependent, so it's bad luck for you that you don't have access to that sort of info. However I'd still advise asking if you haven't already because there's nothing to lose, and even a bit of info might be useful.

For example the breeder my starting mice are from had advised me that my bucks should be able to stay together until they're either 5 months old, or they're used for breeding - whichever comes first. But equally he took on some adult stud bucks from another breeder who happily stayed together for life, which was very different to what he was used to.

Either way, 5 weeks does sound very young an age for seeing falling out though, so yeh, I'd keep the group for now. But keep close attention to them as they age into adults as little tiffs can quickly escalate into more serious injurious fights.


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## Lilly

As mentioned it really is very line dependent and partly how quickly they mature. I have had 3-5 week old bucks get aggressive with others and I have some bucks that can happily stay in a group and act nicer together than does.

In your situation I would try it, keep them together as long as you're not planning to breed them and they are together from a young age and if there are signs of aggressive behaviour like scabs you may have to rethink it or find the aggressive one and feed him to a cat first

The "impossible to keep bucks together" thing is advice that is usually given to deter new breeders and pet owners from trying it when they're not fully prepared for issues. But I also know some breeders, including myself that will happily keep bucks together until they are old enough to breed as long as they're put together when young and its a special interest of mine to see the effects of having a buck group. It doesn't always work out but at the moment I have a group of 7 of different ages (the oldest being 6 months and bred several times successfully and put back) and I am able to put weanlings in with them, they act like does and so far I have seen no fertility downsides of this... on the other hand I would never dream of doing this if I wasn't at home for 99% of the time and they're on the desk right next to my computer screen. I am worried that a few generations down the line I will end up with fertility issues as have been reported by some British breeders, but I am not selecting for it and any buck that shows any sign of aggression in the first day even if its mild is housed alone.


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## Teenybits

Thanks for the sharing Torin and Lilly. It helps to learn from breeders who are already doing so. I intend to keep the group for trial and would likely not put a buck back once he is used for breeding though. The other day, I put in some does that had been with another buck but I know was not bred, the first thing is the buck followed his sense of smell and didn't welcome the does at first contact but was ok when he further "check them" out. So I know it would be terrible if it had been a buck. At least for that buck, I know it's a no go. Is it ok though for a buck to be house singly all his life except for breeding at times?

Lily, i would also be interested to know how your group of bucks behave as they mature more.  I probably won't be keeping mine together beyond a few months. I was concerned how soon any fighting might occur before that. 6months sounds positive as it is


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## Lilly

Many breeders will house bucks on their own all of their lives with no issues. Even in the wild males will not really live together for this species.


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## FlufferNutter

I've kept brothers together up to 12 weeks, at which point it seems as though a switch gets flipped and my boys start fighting at the next cage clean out. I've never tried being more careful about maintaining the scent of the cage, which might help. But in my mousery 12 weeks is more than enough to know if they are breeders or feeders.


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## Teenybits

Ok, I Guess it's no choice then. A mousery can only hold that many bucks with the space constraint and time.

Fluffernutter, you are probably right on the switch flick, with a change in litter, they must all smell different now! Was it the displacing them in a holding bin while their bin is being cleaned out that they start to fight or back to their own bin with new litter that it happen?

Oh on fighting, how do one actually break up the fighting?


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## Lilly

Not with your hands or you're highly likely to get bitten (think of trying to break up a dog fight)

Usually I have a toilet paper roll or something similar and put it in between them then use it to scoop them up


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## Teenybits

Ah ok. I was just thinking what are the methods with mice. I am probably not using my hands as I have ever gotten bitten while trying to separate male cats fighting.


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## Lilly

Split up with something safe and pick up by the tail straight into another container works too, they can be worked up after fighting and bite anything near their mouth


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## Lilly

Teenybits said:


> Lily, i would also be interested to know how your group of bucks behave as they mature more.  I probably won't be keeping mine together beyond a few months. I was concerned how soon any fighting might occur before that. 6months sounds positive as it is


I actually reintroduced one of my bucks yesterday after being bred. He was a virgin buck that has grown up in a buck group since weaning. He was with two does for about 10 days and I'm pretty sure one, if not both are pregnant so there didn't seem to be breeding issues with the first generation. Upon putting him back with the bucks no one kicked up a fuss, everyone acted like that is how they had always been, not even a single squeak. I have worse behaviour putting does together.

I do not recommend this though unless you really know your lines.

Time will tell if the next generation is as fertile and if as I go down the generations it starts affecting fertility. But for now it has let me keep multiple bucks of each line so if I lose one for some reason I haven't gone several steps backwards.


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## Teenybits

That's sound great. You have mention fertility with the males grouped together; are you saying that males put to together usually have Ferility affected?


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## Lilly

Not really in males housed together but I have read some breeders from the UK say that in lines where bucks are chosen for being passive and able to live together, they are not as fertile. I do not know the extent of this or if its always true, so I am going to keep an eye on things and see.

I don't chose them by whether they are passive, but when weanlings are put with the group they just seem to be able to stay with them so far in my lines


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## Teenybits

yes I had a feel the tendency to be territorial could be hormones other than species-related. Afterall in the wild, it's survival of the fittest.


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## Teenybits

The male group was together for a while before I had to cull because I don't have the time to maintain. I had putting back some males I had taken out for breeding and when I tried putting them back, fighting happens so I can't do for these boys. Cutting down my breeding to breed more for interest now cos it's quite impossible to have them just for cat food. If I have alot more space and time, it would be worth considering.


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## PPVallhunds

The big problem you have with keeping bucks together is that you will never know if its going to work or not. It will be find until the day its not fine anymore, which sadly could end in a dead buck.

Ive kept bucks together in the past, when I had pets a had a male group who was split out from a bigger male group. There was a defernat top and second buck in the groups. The bigger male group was run by a horrible buck a real nasty piece of work so was his second in commarned. they would randomly pick out a male to attack and bully. The smaller group came about as one male was almost castrated by the horrible buck so I took him out, the two smallers males, one who would get bullied a lot and another buck to start the new group and then got rid of the big group. (it was only there as we had 30 mixed mice come into work one day).

The new group worked perfectly, the almost castrated male was the top buck and he was firm enough to keep everyone in there place but never took it too far, the second was a son of the horrible buck and he had some of his temperament but the top buck kept him in line when he over stepped it. no one ever got injured. This group lasted well over a year until only two bucks were left (top buck was rehomed to a pet home and the two small ones were killed off due to spot on treatment). When I decided to breed which took ages they were crappy breeders, I made the mistake of putting them back together thinking it would be fine. the next day the second buck had mauled the other male so bad I had to put him down.

since then its failed. Ive had a pair of bucks who lived together for another breeder but once I had them I noticed one would constantly bully the other so I split them as I don't think its fair to make one live a life of stress. Ive had litter brothers who started fighting at 6 weeks before but most can last until 8-12 weeks if I don't clean them out much or properly. Once I pick who is staying now they get split up I don't think its worth the risk now.
I even had a buck try to pull another threw a tiny gap in a box I was transporting them in, had to pull the car over and break them up.

I have defernatly found the males who are better with other bucks tend to be the ones to take longer to mate a doe.


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## Lilly

My buck group is a little different to yours and although I am under no illusions that I can repeat it will last forever its worth the risk for the situation I am in (in my opinion)

I am at the stage where I am trying to get together a lot of recessives, get things settled down and as a result am having to keep a few different bucks for each line, I can either drop down to one on his own and have a harder time and cull the rest, or keep more in a group and hope that I have a second chance if anything happens to the first. I also am in the situation of being home 90% of the day and having them in the same room right by me so if any problems start I may be in the position to do something about it.

My group is quite large about 11 bucks and none of them act dominant, all are really sweet and two of them have been bred after being in the buck group since they were weaned, and got the job done within a week of being in with the does. If any mouse shows any sign of being bossy, even if there is no blood then they get pulled out on their own.

I am worried about future generations being bad breeders, I seem to have luck with the ones I'm breeding if I breed them fairly young (2-3 months) and have them in the buck group before and after, I can generally put them back and then take them out for breeding and have them do decently, so we'll see how future generations are with this, while also keeping the main buck on his own and just using this group as a way to help out while I get established.

I am thinking of splitting up into two separate buck groups soon and adding some new additions I got from another breeder that came to be in a group and seem pretty laid back, will see how it goes I guess.

I don't find that my group lives life stressed and on the edge, there are less issues so far than in many doe groups and they cuddle together in a ball, eat together, two merle brothers in the group use the wheel together, play with the same toys together etc.

I really would not recommend this as something that should be done... but in this case so far it is simply amazing, the bucks are a lot happier than some of the ones I have had to have on their own.


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