PTZ network cam for livestock monitoring

Hi lads,

Can anyone give me some advice in choosing a PTZ network camera? I've been looking for weeks now and I'm finding it hard to make a decision. I want to use it in a shed approx 25m x 6m for monitoring lambing and calving

The features I want are Dynamic DNS support, optical zoom (I think this will useful for lambing in particular) and IP51-rated.

Infra Red is not vital since there is lighting in the shed that can be turned on a night, however it is important that it performs well in relatively in poor lighting since not a lot of sunlight gets into the shed during daytime.

Recording is not required.

Obviously I want something that will last too.

There's a huge jump in prices when moving from pan-tilt to pan-tilt-zoom, I notice and there's a lot of Chinese stuff out there that it's hard to make a judgement on how good it is.

I have been considering the AXIS P5512 based on Axis's reputation but it's expensive (for this purpose) (approx €1,100) and not HD (I'm not sure how important HD would be in this application however) The HD Axis offering, the AXIS P5534 is well out of budget unfortunately.

Does anyone have any recommendations for a decent PTZ camera that can be used for this purpose? Thanks