My favourite thing is watching cattle, especially calves, being let out to grass after a period being housed.
Back to the bullying topic... The explanation given above, of the heifer stirk having lost its mum's protection and therefore having to find its position as an 'only beast' makes perfect sense to me.
Val Porter
guru of cattle behaviour, explains that cattle do not have a straight pecking order A pecks B, B pecks C, C pecks D, so A in fact pecks B and C and D, B pecks C and D, etc, but highly individual interactions and statuses. So that with cattle, A may bully B and D but not C, whereas B does bully C - and you can't predict whether D can bully C, you have to watch to find out.
Val Porter makes the point that therefore introducing a single beast causes quite a bit of disruption, as it has to find its position with every other beast in the group. Whether removing a beast causes the same amount of disruption I am not sure - but clearly if it leaves a youngster unsupported, then it's similar to introducing a beast.
Cattle welfare guidance requires all cattle to be kept in groups of their own age range, as a younger animal with a few older ones will be so bullied it may not get to food at all. If you only have three beasts, then you can't do this, clearly - but then hopefully one bully cow won't stop both the other animals feeding completely. It is best to keep a good eye on them though, until you are sure that the most timid animal is getting to eat and sleep enough.