I'll second that My klaasi molted in November and immediately drained it's water dish, plugged up it's hide and hasn't been seen since. And my hamorii sling burrowed for 2 months and then molted. Hasn't come out yet and hasn't eaten (or drank?) for another 2 months. It is still moving around down there though.It depends on the species too + the individual t. My t albo's (1.5" approx) were fed 2x a week, grow pretty well and 2 of them fasted 1 week before moulting. But my LP sling won't usually feed 2x a week. Every 7-10 days for it yet doesn't fast longer than a week or 2.
Then you have the Brachy slings - auratum + smithi. Weekly feeds and hella long fasts.
I literally cheered seeing my smithi eat, as it was weeks after it moulted (it had a long fast before). It's a tiny sling too, like a microdot. Wasn't much of a size increase either. Seems healthy enough, and pretty speedy when it wants to be too lolI'll second that My klaasi molted in November and immediately drained it's water dish, plugged up it's hide and hasn't been seen since. And my hamorii sling burrowed for 2 months and then molted. Hasn't come out yet and hasn't eaten (or drank?) for another 2 months. It is still moving around down there though.
Powerfeeding is a throwback term used with reptiles. From what I understand it doesn't really work on tarantulas. Reason being that they only eat so much before they molt. The end result is usually a LONG fast as they no longer need food to complete the molting process.
My T albopilosum was fed every three days for a month. He burrowed for 2 months and sealed everything off. Went in at about 2/3" and came out at least 1.5". I think he ate enough for 2 molt cycles. At this age power feeding was somewhat useless as he was growing like a weed anyway.
My E campestratus got fed every 3 days for about a month. Started refusing food in August. I thought a molt was just around the corner. Boy was I wrong! She finally molted at the end of December and had a sketchy molt. Ate her first meal in January. This is a 1/2" sling that went 5 and a half months with no food. This species is very slow growing and all the power feeding did was cause a long fast.
Your bird eater should be growing like a weed anyway. I personally feed my small juvies once a week.
The other thing about overfeeding is this: adults and larger spiders can get abdomen injuries if overfed. These occur usually on the underside of the abdomen due to "dragging" injuries.
Sorry for the long winded reply. Just thought I would share what I know being active in both reptile and tarantula keeping.