Here's the forecast for this weekend here in New Hampshire. I have packages arriving on Saturday AM. I'm south of the lake regions.
Saturday: Rain all the way to the White Mountains will fall as a mix of rain and wet snow in the North Country. As winds wrap around a developing storm offshore, colder air will wrap back to the south and change the rain to wet snow from the White Mountains all the way to the coast. Several inches of snow could accumulate, especially where the changeover occurs first, the White Mountains and higher terrain around the Lakes Region, Mount Washington Valley, Sunapee/Washington area and through the Monadnock Region. Highs: 36 to 45 in the morning, then dropping by afternoon.
Sunday: A mix of sun and clouds to mostly sunny skies. Partly sunny with a sprinkle or flurry over the North Country and White Mountains. Windy, but milder with Highs: 39 to 52!
So my question, would you shake or wait?
I'd feed them and put them in a dark corner of my house (inside where it's warm) and feed them again on Sunday morning and afternoon and put them in on Sunday afternoon. Unless the weatherman is wrong, as he usually is. If it's calm and not raining on Saturday for brief spell, I might go ahead then.
I'd wait if the next day is going to be rather nice. If not then just do it. But then again I've done it even knowing the next day will be nice so the girls get the extra day for comb drawing :> )
Just looked at the weather forecast for Fremont, NH at weather.com. Looks like bad luck on the timing of your package arrival. Supposed to be in 30's and low 40's until next weekend and nasty Saturday into Sunday morning. Sunday is forecast to be the best day for installing until Friday. I'd install Sunday midafternoon.
Good luck with whatever you decide...