Crabbing and that blowing through a straw sound is pretty common in my two girls who are best friends. This happens maybe once a day when they will get in an arguement about the way they want to sleep-crab and 'whistle' and roll around and then go right back to bed. Or when Vestral wants to get up early and wakes up Wavern who wants to stay in bed. They are social creatures who are very talkative, so this is to be expected. However-what are they doing when they 'fight'? Are they balling up? If they are just showing who is who I think that is normal-but if one is going after the other and literally attacking them this is not good. Hopefully someone else can explain the difference better. My girls have never actually fought so I can't say for sure, sorry!